My gearbox revision thread

[goldnsx]

The input shaft of my gearbox (totally 190k km but revised with short gears/4.23 at 80k km, so untouched for the last 110k km) makes some noise at idle with the clutch pedal up and the 5th gear was making some kind of the sound of marbles at 1500 rpm cruising around.

First taking the gearbox out. Special thanks to Sylvian for borrowing me his lift.

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Opening the box, at first sight:
- snap-ring ok
- countershaft bearing (the one at the snap-ring) ok

Not sure what to think about the gears. There are spots and even rust ??? on them? I didn't lend my car to 007 for diving in the sea...:)

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5th gear: mysterious signs of wear. I've to admit that it popped out on the German Autobahn 2-3 times but that was back in 2008 or so. Something is wrong here. Of course, I use the 5th gear a lot (a lot of cruising). Opinions?

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I already have new main bearings and all synchros for sure to go in. Will do a lot of measurements by the SM tomorrow.

Expert advice warmly welcome, thanks in advance!

[goldnsx]

Reverse gear synchro teeths. While the synchro ring looks good the reverse drive gear looks strange. The sleeve looked ok. I've compared it to another gearbox we did in the past and it looked about the same.

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[Kaz-kzukNA1]

Hi, goldnsx.

As you went for the final ratio change, you were forced to replace the countershaft, final driven and oil pump. I presume you replaced the countershaft bearing at that time.

With the short gear ratio, you were forced to replace the mainshaft (main 1st, reverse, 2nd directly machined on it), counter 2nd, main/counter 3rd & 4th gears.

I don’t know the base gbox no. of your NSX but looks like there is no washer between the main 2nd/3rd gears so I believe you got the later spec mainshaft which is good.

I'm afraid that main 5th gear needs replacing.
As it looks like you are replacing all of the synchro related parts, not much to say but that damage is the typical sign of driver accelerating to the limit in 4th gear and then quickly shifting up to 5th.
As you opened the gbox, you will notice that compared to the 3rd and 4th synchros (both using the same capacity), 5th one is much smaller for some reason and that is the main reason for the damage.
Addition to this, the inertia of the CL will play the big part against the synchro capacity but I'll leave it for now.
Just a matter of interest, what CL were you using when you first noticed the 5th gear issue?

I can't tell the spec of your 5th shift fork.
Could you take the photo of it to show the shape of the craw/fork?
Honda did change the shape/spec of this fork as there were some reports of broken 5th fork in the past.
Since you opened the gbox, best to replace it if you are using the old spec one.

I believe you selected the proper shim thickness for the new mainshaft but may want to double check it.

What MTF were you using?

Personally, I don’t like the Honda own synchro design without the synchro key but no options…..


Kaz

[goldnsx]

Kaz, thanks for your reply.

Back in 2005, my tranny (1003042) of my 1991 was built with new bearings, FD4.23, new mainshaft, new countershaft and short gears 2-4 (1st and 5th not changed), new synchros and main bearings and new snapring. I always had the OEM twin-disc clutch kit, being the first one, so will replace it now too. Always filled with MTF III, changed every 20k km.

I only have a bad picture of the shift forks but they never have been changed so far. EDIT: I've measured them and they are about 0.05mm thinner than the standard. The clearance between the shift fork and it's corresponding sleeve is still within specs (around 0.60 mm). Service limit would be 1.0 mm, so I think they're good to be used again.
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Thanks for the hint for the 5th fork failures. Is the newer design interchangeable with the old one?

I just got home and am still upset (and depressed too) because something is wrong with the countershaft I've been working on today. I'll have no sleep tonight...
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I've changed the 1st/2nd synchro/hub/sleeve as a complete set. Before, I've measured the clearance between the 2nd and the 3rd gear (according to 13-30) and found no play at all but the 2nd gear was turning. The standard clearance is 0.04-0.10 mm. I've pressed the 3rd gear onto the shaft and now the 2nd gear is NOT turning, neither so the synchro ring (this are expensive new parts!). The synchro also looks too far of the gear. Now, it looks like the 2nd gear synchro is pressed and it that's the case it's damaged I think. If I'm lucky the spacer collar is just a tiny bit too small.
In the first two pics is the 1st/2nd gear hub/sleeve. One side is 6.5 mm deep and the other is 7.5 mm. I've installed it the way the old one came out and backed up the the installation with the pics I've taken before. The tiny groove on the outside (pic 3) is towards the 1st gear. The SM doesn't mention anything about that.

I'll need some motivation before I go on working on it...

Thanks for listening.

[ozon02]

Hi,

Honda 5th Fork change

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Left Old
Right New

[britlude]

Hi,

Honda 5th Fork change:

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Left Old
Right New

bad pic link.....

[goldnsx]

The mystery with my 2nd gear has been solved.
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The new synchro ring was damaged while pressing the 3rd gear on the shaft. Even after doublechecking every step and consulting the manual (and my brain) it must have misaligned when I was fidling with the 3rd gear. I regard it as bad luck or as a puncture in a new tire, it's only money... I'll get a new one. I testfitted the third gear and there's a space of 0.05 mm between 2nd and 3rd, that's fine.
I'm glad that no other parts were damaged.

The hub/sleeve story ended like this: there are small pictures (on the left) in the exploded diagram. By most of them you have to think about a minute or two what area they could refer to and what they are willing to tell you. I don't blame the SM but I guess I was expecting a note or a word of caution. Anyway, it was installed correctly.
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Mainshaft adjustment
I was verifying the selected shim(s) that the former installer choosed. It had two shims in it (1.00 mm and 0.65 mm = total of 1.65 mm) with the old mainshaft assembly. There's a note in the SM that you should NOT use two shims (I don't know why and the former installer didn't care). I've removed the ISB and measured:
Averaged 2.35 mm - 0.12 mm (bearing higher than case) - 0.99 = 1.24 = max shim. ...-1.06 = 1.17 = min shim. So it needed 1.20 but it had 1.65 mm. Not sure but that's my guess why my input shaft bearing made noise. Both main bearings are still fine but under too much pressure. Comments are welcome.

Question of the day: I need a 1.20 m shim and the thickest shim in the parts catalog is 1.15 mm. Should I install 2 x 0.60 mm? Is it really important to check the mainshaft clearance with the special tools where you pull on the mainshaft and check if the clearance is 0.14-0.21 mm (page 13-42)?

Another question: how to get these two babies out?
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The oil seal is already out.

[ozon02]

Hi Goldi,
I have SM from USA (Acura) is writen:
"Do not use more than two thrust shims" (ist geschrieben)

[goldnsx]

Yes, that's what I've read in the SM too but I'd like to know what the reason is. The former installer took two shims and he did a lot of NSX gearboxes. I don't see a reason against using two shims.

As the bearing I measured with was used for 110k has more play than a new one (actually even a new one has some play built in), I guess that the clearance will be reduced with a new one. If it's reduced by 0.20 mm I can go with the 'standard' shim (1.00 mm). But I'll have to measure again as soon as the mainshaft is rebuilt with new parts.

[ozon02]

as I understand you write two issues:
1.
"makes some noise at idle with the clutch pedal up"
2.
"the 5th gear was making some kind of the sound of marbles at 1500 rpm cruising around."

1.
may be ball bearing in flywell issue?
2.
I would go in the direction of Kaaz mentioned

and I am doing all the measurements according to the instructions (needle bearing surface etc.)

[darock]

Thanks for documenting all this!

This will help me a lot when doing my gearbox. I have some whiny gearbox noises in fifth gear and also a little gearbox leaver movement when getting on and off throttle in fifth. The housing of my gearbox looks to be replaced at one point. I assume it was a snap ring issue. I think the one who did the install messed up the clearance of at least one gearbox shaft.

I was hugely lucky right before Christmas. Found a near complete set of gearbox rebuild parts about 4 streets away from my house for about 2/3 the current price including parts that are NLA. I didn't even know there was another NSX nearby. Christmas gift to myself :D

Bernhard

[goldnsx]

"the 5th gear was making some kind of the sound of marbles at 1500 rpm cruising around."

1.
may be ball bearing in flywell issue?
Haven't checked that so far but will do for sure. Anyway, a complete new clutch will be installed.

I think that the 'sound of marbles' in 5th was more due to the play between the worn synchro sleeve teeth of that gear (see pic above) and maybe the sleeve/hub (I didn't see yet). In 4th at 1500 rpm the noise was not there but would have been too if it was a bearing. I first thought about the countershaft bearing with the snap-ring in as it's the nearest to the 5th gear and is prone to go bad but it was really like new (surprised). I think Kaz is spot-on with his explanation even though I rarely shift from 4th at WOT in 5th (speed limit here 120 km/h) but I do drive in 5th >80% of time (fuel saving, haha). Also, I'm CTSCed. So it could be just wear and the popping out on the German Autobahn back in 2008. More over this, the 5th gear needed a little bit more force to engage when the gearbox was cold but was ok when warmed up.
In my friends tranny the synchro sleeve teeth were worn also BUT not like mine. The teeth looked like rounded off you normally see when a gear grinds while shifting.

[Kaz-kzukNA1]

The later design 5th shift fork is interchangeable without other parts involved. Just the craw/fork strengthened by new shape. Just remember to replace the spring washer.

You already found the answer for the sleeve and hub orientation. The tiny groove on the sleeve and the channel or the diameter of the collar of the hub show the orientation.

Despite the usage of the straight edge, I never felt confidence in selecting the shim using that A+B or A-C measuring method.
I just use it as an initial guidance and move on to the final inspection target of 0.14 – 0.21mm.
You don’t need the SST.
After tapping the mainshaft gently, just use the dial gauge and pull up/out the mainshaft using whatever the method you have and then decide the thickness of the shim.

I think now you are aware that there is no problem using the 2 x shim.

Are you servicing the DF?
If not, just replace all of the oil seals and leave these outer race for the tapered bearings on both side of the DF.
Otherwise, you will be forced to replace not just the outer race but also the tapered bearing at the same time.
If you have to, CL case one with oil guide ring is not too bad as you can punch it out from behind.
For the trans case one, normally people will tell you to heat up the case using the heater gun or very hot but not boiling water but I never had any luck using this method.
It just doesn’t want to come out or even move a tiny bit.
For this, I use the commercially available race removal tool that hooks the race edge from inside while heating up the case with the heater gun.
If the race is not on the gbox, you could use the welding trick but too scared for this area.

Kaz

[goldnsx]

Thanks for all your replys, esp. to Kaz.

Today I've replaced the bearing in the clutch case and the bearing races of the diff. As the diff bearing come complete as a set I'll replace the ones on the diff too.

The bearing in the clutch case was tricky to press out. There's a special tool (adjustable bearing puller) from Honda I didn't have. So we (with some helping hands) have used the tools available. As you can see we had to improvise a little bit to pull it out as straight as possible. Heating up the case helped too. For the new bearing a press was used. Note that the two little holes in the bearing are facing upwards.
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Both diff bearing races were pretty simple to get out. Just had to work out in what order. For the 90 mm one you hammer on the oil guide plate first. As soon it's free it leans against the race. So you hammer (with great care of course) until both are out. You have to install the oil guide plate first. Then you press in the race. There were some small marks in the races.

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Next week I'll change the bearings on the diff and then will do the adjustment procedure of the shim at the 75 mm bearing. Till now, a 2.09 shim was used.

I'll set my diff to NSX-R. There a great video on youtube about how to install the additional spring and new plate.

[goldnsx]

A view on the oil pump. There are two marks. When I turned the case around the little spring and ball on the lower right to the oil pump fell out. Now it's installed correctly.

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The release bearing guide showed some wear. 190k km, dirt and no lubricating might have added to this. I think I'm replacing it.
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I had a hard time to take the snap-ring out of the case, no fun job. What a beast!

Mainshaft adjustment
Thanks for your remarks on that. How hard do I have to pull (in kg?) on the mainshaft to measure the targeted 0.14-0.21 mm? Can I use wrapped pliers on the mainshaft and pull it by hand?

EDIT: just came across this video: https://www.youtube.com/watch?v=wEjwISEuyPU
Fast forward to 10:00 where he mentions to check it by hand.

Many thanks in advance.

[goldnsx]

I have some whiny gearbox noises in fifth gear and also a little gearbox leaver movement when getting on and off throttle in fifth.
If it does this I'd check the snap ring immediately by opening the big screw (1/2 driver) and see if it looks broken like the one of asylum recently. You don't want to have to replace more parts than needed.

Good luck!

[goldnsx]

I went on with the clutch job today. I was surprised to see that the discs still had 7.9 and 7.3 mm, not bad for 130k km on them. The red circle points to the roughness but the pic doesn't represent it so good related to the flash light.

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Not so nice was the mid plate:

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[Pride]

Will you be changing the clutch release bearing and release fork at the same time goldnsx???

[goldnsx]

... and the flywheel:

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For the future, I think I've left my 'wild years' behind me. Whenever I think about 0-100 times or other silly things I'll have these pics in mind.

The release bearing was good but not perfect, some little noise. I've taken a video of it. The flywheel bearing was ok too.

As a new clutch is ready to be installed I'll replace it even though the old one would have been good to go for many, many miles but out is out.

Pride: Good point, yes, I'll change the clutch fork too. It was worn quite a lot and I think that this added to the suspicious 'knocking noise' I have observed. The noise went immediately away when I lightly pressed the clutch pedal. Too much play between the shift fork and the release bearing I guess.

[goldnsx]

Happy New Year!

Additions to the broken 2nd synchro. I've tried to replicate why the dual cone synchro was misaligned when mounting it. When you place it in the sleeve the inner ring tends to hang on the bearing and is pushed upwards out of the synchro set. If you mount it you have to push on the inner synchro ring to make sure that doesn't happen.

So, how not to mount it:

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Another question about the mainshaft clearance adjustment. In the initial step I've measured 1.20 mm. When I move on to the final clearance inspection how much has to be corrected? +-0.10 or +-0.20 or even more? I'm going to order the shims in 0.05 steps in the required range (before I spend too much money on ordering all possible shims :)).

Thanks again!

[Kaz-kzukNA1]

Hi, goldnsx.
If you are doing CL service, you may find this info useful.
These are the parts that will be replaced during my CL service although I know you don't like replacing the parts that amy be re-used for some time.

OEM CL set
Flywheel bolt x 8
Release bearing: probably too late but HUK is the cheapest, about GBP42 at the time of writing
Release bearing guide: this is a MUST unless there is no markings or rust
Release fork: this is a MUST
Release fork hunger
Hunger spring
Hunger bolt x 2

Please invest in good quality grease. Honda OEM Urea grease is expensive but very good especially for CL task.

When removing the flywheel, I normally replace the crank end seal at the triangle cover plate if not done for years.

For the mainshaft clearance, you already have 2 x shim from the previous service so just temporarily install the thinner one (I think you have 0.65mm) and carry out the final inspection method for 0.14 – 0.21mm clearance target.
Then, calculate the total shim thickness required aiming around 0.17mm. That's what I normally do unless freshly building the gbox from new parts.


By the way, I don't know how old your friction disc is but the torsion spring looked rusty but not too bad at all for the mileage covered.
Quite often, they are much more rusty and even broken off resulting in not being able to disengage the CL.
On the other hand, the mating surface at the pressure plate, mid plate and flywheel looked to be partially contaminated by oil/grease and also some blue markings…


When you removed the gbox off the engine, did you find any oxidation on the fixing bolts?
If the gbox was removed in the past and care was not taken on re-assembly, some of the mating thread on the eng side could be damaged and you won’t be able to apply enough torque when re-installing the gbox this time.
You may want going through all of the mating thread on the eng side by tightening the bolt with just the finger to see any changes in friction before re-assembly.
I normally apply dash of silicone spray to prevent future oxidation.

Also, having 2 x much longer fixing bolt with bolt head cut off and tapered can be useful as they can be used as the gbox case alignment guide when re-installing the gbox especially if you are doing this task on the floor….


Kaz

[goldnsx]

Hi Kaz

Thanks for your valuable reply.

Release bearing
So I'm going to change all the parts around the release bearing: fork, guide, hunger, spring...

Mainshaft
I'm going to install two new bearings on the mainshaft and put it in the gearbox. Cleaning the contact surface of the two case halfes thoroughly. 45 Nm. With only one shim (standard 1.00) I'm going to measure the clearance. As I expect it to be higher than the targeted 0.14-0.21 mm, so the resulting clearance will be determined. Also, as I don't have the Honda tool I won't be not able to use that much force like the tool would allow, so I'm aiming for the lower half of the deviation (0.14-0.17). I've done some combinations of pairs of shims which allows me to order just 4 additional shims and still being able to get any clearance from 1.00 to 1.40 mm (for example) with 0.05 steps in between. For 1.05 I'd be using 0.50 and 0.55 for example (easier to install too).
I know that I have to do it again as soon as the new parts (new hub and gear for 5th) are installed but I don't think the clearance will be way off then. I just try to avoid to place a second order with weeks to wait again...

Oxidation on the fixing bolts
I didn't see any oxidation. The screws came out by hand without headaches. For breaking them loose most of them were pretty stiff but not overtorqued. I'm going to use less torque on them I guess (well, the one stated in the SM) and use a calibrated torque wrench for sure. I always use ceramic paste as an adhesive. You just have to make sure that you don't torque it too much as the resistance of the threads is lower with ceramic paste, so the resulting torque is maybe 10% higher than intended. Worked good in the past but will check for oxidation again.
The threads of one screw at the rear engine mount were damaged by a complete idiot who must have used air tools in the past. The threads can be repaired I think and I'm going to test if the threads can take 105 Nm or better reduce the torque a little bit.

In this time-consuming project I'll tend to replace more parts than actually needed. For example, the 2nd gear synchro was perfectly good, no need to replace it until I ruined the new part.:( If you can change a part within an hour I'll have a slightly different approach. :)

[Pride]

Hi,
If you are doing CL service, you may find this info useful.
These are the parts that will be replaced during my CL service although I know you don't like replacing the parts that amy be re-used for some time.

OEM CL set
Flywheel bolt x 8
Release bearing: probably too late but HUK is the cheapest, about GBP42 at the time of writing
Release bearing guide: this is a MUST unless there is no markings or rust
Release fork: this is a MUST
Release fork hunger
Hunger spring
Hunger bolt x 2

Please invest in good quality grease. Honda OEM Urea grease is expensive but very good especially for CL task.

When removing the flywheel, I normally replace the crank end seal at the triangle cover plate if not done for years.

Kaz

Hi Kaz.
I am due to replace my slipping clutch assy and have bought the complete OEM clutch kit and separate clutch release bearing, along with new driveshaft oil seals and the crankshaft oil seal behind the flywheel you mentioned.

You suggest replacing both the release fork and guide as a MUST do job, but as they are very costly items, about £650, can you please explain your reasoning behind needing to do this as the Honda dealer doing the clutch job would not be able to get these items at short notice once the gearbox is removed.

The hunger spring is presumably the hanger spring, and lastly can I buy a small quantity of the Honda Urea grease before I take it into the dealers so as to ensure they only use that type of grease when doing the job.

http://www.lingshondaparts.com/honda_car_parts_selection_pfk.php?block_01=17SL001&block_02=M__0300&block_03=21668&block_05=hcr

Thanks in advance.

[goldnsx]

You suggest replacing both the release fork and guide as a MUST do job, but as they are very costly items, about £650, can you please explain your reasoning behind needing to do this as the Honda dealer doing the clutch job would not be able to get these items at short notice once the gearbox is removed.
I've taken a picture of the release fork and will post it later but I've seen that there's pretty much material shaved off after 190k km and using the clutch quite often. So Kaz' suggestion completely makes sense to me. Maybe not in a car with low miles (<100k km?).

They should have the UREA high temp grease I think. If you mention it you'll see their reaction.

[Kaz-kzukNA1]

Hi, Pride.

Release fork wear is easy to tell if you compare the new and old one side by side.
The fork edge where it pulls the release bearing and slides over will show significant wear by the time when you need the CL service.
Remember, this happens when you press on the CL pedal as well as when releasing.

The pivot point 'saddle' where the fork sits in the hanger also shows big wear marking.

If someone didn't use good quality grease inside the pocket where the CL slave cyl plunger sits, you will see rough markings inside the pocket.

All these affects the pedal feeling and the wear at the fork edge and the saddle will increase the CL pedal effort.
When NSX left the factory, the CL pedal was like feather light and smooth.

Release bearing guide is where the release bearing slides over when the CL pedal is pressed and released.
NSX CL uses much higher friction co-efficient materials that over the years, CL dust, debris, etc are trapped in the grease and depending on the quality and amount of the grease used, release bearing could no longer slide smoothly over the guide resulting in noise, vibration or even sticky feeling through the pedal.

In UK, unless you track your NSX regularly, you should be able to cover lots and lots of mileage with the same CL (I can go more than 100K miles in UK but only about 30 – 35K miles in Japan using the same driving style before I start thinking about CL service through the pedal feeling) so I don't see the point of guessing how long the existing release guide can survive.
If you see any rust or marking, you must smooth it out before re-using.

They are not that expensive if ordered from Japan. Try one of the NSXCB vendors to get the parts from Japan. Honda Japan is closed for the new year holiday but they will be back in the office from 4th.


I only use Honda Urea grease UM264 (41211-PY5-305). It's dark grey sticky grease. Fairly expensive for 200g….
Outside of Japan, Honda/Acura normally uses Honda Urea grease 08798-9002.
It's green colour, 150g and much cheaper than UM264…..
Just make sure to pack the internal groove of the release bearing with the Urea grease before installation.
You are going to rely on this packed grease until the next CL service.

Kaz

[goldnsx]

I have the Honda Urea grease 08798-9002 here and going to use this one. In the US, there haven't been reports of failures due to it.

[goldnsx]

That's why you want to check the release fork:

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I've changed the diff bearings today. While the races were pretty simple to take out the 90 mm bearing on the diff was a pain to remove. We had to grind the cage off and heat the inner race up. You can't really grab below the bearing to pull it out. The good news is that all is mounted now. We heated up the 90 mm (200 degrees C) and it just fell on the diff without any problems.

After cooling I could mount the diff in the tranny case and also fitted the mainshaft with two new bearings in the case and took some measurments of the mainshaft clearance and diff starting torque. The diff itself is at 88 Nm but I'll mount the Type R plate.

Readings
Mainshaft clearance
I've calculated a shim of 1.20 mm and started with the 1.00 which was used in the past (together with a 0.65 mm). I got 0.11 mm of play. So a 0.95 mm shim would be perfect.

Diff
We gave the diff a long period of cooling down before measuring. The bearings have been slightly oiled. I've reused the 2.09 mm shim the diff had installed before (1.97 mm is standard) and we got readings below 2 Nm. As 0.03 mm are said to attribute 0.3-0.4 Nm (by the SM) I'm going to try a 2.18 and maybe a 2.27 (the thickest shim available).

[goldnsx]

I'm afraid that main 5th gear needs replacing.
As it looks like you are replacing all of the synchro related parts, not much to say but that damage is the typical sign of driver accelerating to the limit in 4th gear and then quickly shifting up to 5th.
As you opened the gbox, you will notice that compared to the 3rd and 4th synchros (both using the same capacity), 5th one is much smaller for some reason and that is the main reason for the damage.
...
Kaz

I've found a different possible explanation for the wear on the 5th gear: long gearing, WOT in 2nd and speed limit. I was on the German Autobahn only a few times. But what I've done in the early years on normal roads quite often is shifting from 2nd at redline to 5th directly. I did this with a small delay but who knows the speed of the shafts in the gearbox by that time? Anyway, the 5th gear has to do all the synchro work, and being the smallest it wears out. Since several years I don't skip gears anymore as I've heard of the problems people/Honda had with the 6speed gearbox in the S2000.

[ozon02]

Thanks Kaaz for your hint:

"Also, having 2 x much longer fixing bolt with bolt head cut off and tapered can be useful as they can be used as the gbox case alignment guide when re-installing the gbox especially if you are doing this task on the floor….

for me it is a very valuable

I thought about it (special bolt from Germany-www.boellhoff.com/de-de/produkte-und-dienstleistungen/spezialverbindungselemente/prozesssicheres-verschrauben.php):

https://www.boellhoff.com/files/jpg1/navitight-prozesssichere-verschraubung-einbau1.jpg


....your solution is better

[goldnsx]

A little update. Took the flywheel off today and changed the 'KWS' (I always have to think about Porsche whenever I change one of these).

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Still waiting for parts...

[Nick Graves]

Kurbelwelle Simmerring, presumably...

[goldnsx]

Yes, if you google for 'Porsche' and 'KWS' you find 100'000 hits to the 'Porsche drama'.

[Nick Graves]

:D

Well, I found out I should have written it as a single compound word, too! Kruckstockschaltungsgestange is one of my favourites.

There's an awful lot of occurrences for something that's supposed to affect only a small percentage of engines - guess they must'e made millions of engines, then.

[goldnsx]

It's a widespread Porsche problem which dates back to the 996 AFAIK. But <=993 were far from being dry under the engine. German quality... My wild guess is that they shaved off 1 Cent of production costs and ended up like VW with their timing chain drama.

I didn't have a tool to install the 'KWS' on mine but I took special care of it. I've mounted the flywheel today, Loctite blue, 105 Nm, several steps in a crisscross patern, 20 Nm, 50 Nm, 80 Nm, 105 Nm. Old one: 0.03 mm runout, new one 0.04 mm runout. Tolerance for new one: 0.05 max. All fine then.

[Nick Graves]

The intermediate shaft failure was even worse - simply down to very poor bearing design.

[goldnsx]

The parts have finally arrived at the dealer in Japan, faster than expected. Next week, I should be able to continue the tasks...

[goldnsx]

Diff with the NSX-R plate, very slight difference between the two.

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Mounting it:
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Honda tools rule!
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The diff is now at 170-180 Nm instead of 88 Nm.

[goldnsx]

Mainshaft. Something is fishy with the 5th gear, wear and rust. Everything has been changed: 5th, hub/sleeve, collar, needle bearings, ball bearings.
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Working on the rest tomorrow: shift forks, intermediate axle (new bearing, new seals).

[goldnsx]

Intermediate shaft

Pressing out the bearing:

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new one in:
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new seals and grease and finished:
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[goldnsx]

Shift forks, quite easy to install.
12831 12832 12833

[goldnsx]

Testfitting the gearbox (without sealant). Reverse gear needs special attention. You don't want to install it like in picture no. 2. For mounting it the mainshaft has to be pushed up about 5-10 mm. If you lift it up by the sleeve or the gear you can end up with a damaged synchro. It should be lifted up by the axle with the correct orientation of the pin in the lower section of the shaft to match the tranny case.

12834 12836

New ISB seal and release bearing guide.

12837 12838

Testing the gear selection. All fine.

12835

[goldnsx]

Greasing the clutch. What do you think? Too much or too less?

12841 12843 12846

[goldnsx]

Clutch disc orientation. There are white marks on the single discs. But also pink ones. Not sure what they are for. The SM says that the marks near the spring cages should be 180 degrees of each other. Installed like in this it looks like in pic no. 2. Correct?

12848 12849 12847

[Kaz-kzukNA1]

The key for the greasing is to fill up the narrow internal recess/groove/channel of the release bearing with the Urea grease.
You can see the internal recess in the 1st photo of your post #42. There are plenty grease in there but doesn't look like filled up.
Makes difference after many miles.

The balance marking is the one on the torsion spring plate and it’s the one facing you when installed at the correct orientation.
In your photo, it’s the white one on both discs.
In your 2nd photo, because you pre-installed the two friction discs on the main shaft, can’t see the white marking (they are facing towards the trans case side) but please set them with 180deg offset between the two discs.
You can’t see the pink ones once mid plate is installed any way.

Please align the triangle markers on the flywheel/mid/pressure plate.

I like your new release bearing guide.
Must item to be replaced for my CL service.
Even tiny amount of rust or wear could cause friction resulting in uncomfortable CL pedal feeling or not smooth sliding movement of the release bearing.

Kaz

[goldnsx]

Thanks for your extended reply, Kaz.

The new release bearing guide is very nice indeed. I've checked the diameter and the old one. It was still the same size (+-0.01 mm), even though it had grooves from wear in it. Just remember that it had 190k km on it. The clutch pedal was still smooth and light.

Dust must have contributed to the wear on the tranny side of the release bearing guide. I think I'll give it a little bit more grease there to prevent it but I'm not sure it that's a good idea (grease attracts dust). You can see that in the picture above. But in that location the grease will not find it's way onto the clutchdiscs anyway.

I'll recheck and repack the grease in the release bearing groove.

I wondered if the offset of 180 degrees has to do with the orientation of the springs of the clutch discs but it doesn't seem to depend on. In the pic above they are installed with an offset of 180 degrees and the springs are not parallel. Anyway, if it should be 180 and someone in the factory took his time to set the marks I'll trust them.

Tomorrow I'll install the clutch and prepare the gearbox for the reattachment on the engine. That's the next (and last) difficult task.

One last question: should I initialize the mid plate of the clutch before or after the installation of the gearbox? Is there a chance that it will move again while mounting (forcing) on the gearbox to the engine?

[austrian type-r]

nice write up. You cant initialize the clutch when the transmission is mounted.#

btw: was it easy to remove the intermediate shaft from the bracket? This is usualy a pain! IMO the design here could be better. Too bad the shaft with bracket can't get removed when the tranny is mounted. I always keep the shaft and bracket together and I remove it when I pull off the tranny from the engine. I pull out the engine anytime, even when just the clutch has to get changed, cause if this is the case, usualy more service has to be done anyway to the engine. Pulling out the whole power-train is not much more time consuming compared to just removing the tranny from the engine when all is installed in the car. I can not imaging people doing valve adjustment and timing-belt service when the engine is in the car.

[goldnsx]

I've mounted the clutch today. Thanks to ATR, I'm going to initialize the clutch before mounting the tranny.

12850

It was not a perfect day. I just wanted to place the tranny under the car but then decided to mount it. Please guess what I've forgotten...

12851 12852

Anyway, one problem was that the gearbox stood at the front engine mounting. I think I'm going to support the engine and loose the front engine mounting more. I'm exhausted for now and will give it a try in two days I think.

ATR, intermediate shaft

I had no problems removing the intermediate shaft from the bracket, not now and not about 8 years ago. But I've used grease on the contact area back then.
I'll second your opinion about having the unit out of the car. You have a fully equipped workshop but I have to use the tools that are available to me. A motivation to try it was when I saw here on the forum that people have done it in a similar scenario. Guess what I'm planning for next year? TB with the engine IN the car. Yes, I know I always said...I'll have a deeper look at it and might give it a try. It's much simpler than gearbox internals...

Greasing the release bearing

One note to the remark of Kaz that the groove in the release bearing is not completey full of grease. When I put grease in there it was and looked full. But if you mount it over the guide once the grease 'works it's way' and that's how it's going to look like in the release bearing guide when you take it off the guide.

Time for a break for me...

[austrian type-r]

Don't know what you forgot, but maybe the shift fork?! *g*

[Pride]

I've mounted the clutch today. Thanks to ATR, I'm going to initialize the clutch before mounting the tranny.

Greasing the release bearing

One note to the remark of Kaz that the groove in the release bearing is not completey full of grease. When I put grease in there it was and looked full. But if you mount it over the guide once the grease 'works it's way' and that's how it's going to look like in the release bearing guide when you take it off the guide.

Time for a break for me...

Hi goldnsx, sorry to see you had a tough day but so far your repair thread looks amazing, you're obviously a competent automotive engineer/mechanic.

I'm just about to replace my complete clutch assy including new fork, release bearing and its guide shaft.
How much urea grease did you manage to put into the release bearing groove before you felt it was a sufficient amount???

Also what do you mean by "initialise" the clutch before mounting the transmission???

Cheers.

[austrian type-r]

Also what do you mean by "initialise" the clutch before mounting the transmission???
Cheers.

That means you need to adjust the clutch so there is equal play for each friction disc. If you don't do it, you have more wear on one disc. Another probelm could be that the clutch will not floating free when the pedal is not pressed, so you will not be able to shift. It is a must to initialize the oem clutch.

[goldnsx]

Hi goldnsx, sorry to see you had a tough day but so far your repair thread looks amazing, you're obviously a competent automotive engineer/mechanic.

I'm just about to replace my complete clutch assy including new fork, release bearing and its guide shaft.
How much urea grease did you manage to put into the release bearing groove before you felt it was a sufficient amount???

Also what do you mean by "initialise" the clutch before mounting the transmission???

Cheers.
Hi Pride

A 'normal' mechanic would have filled the groove of the release bearing by the SM and wouldn't think about it. Well, it's not his car. :) I watched a lot of videos on youtube and all say that too much is bad. The release bearing fits tight on its guide (but slides without any resistance of course) that it only holds a small film of UREA grease on the guide except for the groove in the release bearing itself. First, I've put a small film (barely visible) of UREA grease on the guide. Then, I've filled the groove and took care that it was only slightly more than expected. I then tried to catch any overmuch grease with my flat finger around the inside of the release bearing but not too deep in there, just until the groove where you don't want to remove the grease again. This procedure has been done from both sides of the release bearing. I then testfitted it on the guide. It looked like in pic 3 in #42. At the end you can see a ring of green UREA grease which I wipped off in the end. Not sure what Kaz would recommend here? When I took the release bearing off the guide. After this the groove looked like in pic 1 in #42. The grease in the groove seems to be 'sucked' out of the groove partially.

ATR
Yes, I forgot the bloddy release bearing fork. Asylum forgot it, I forgot it. I hope Pride won't forget it too. :) Will have to take the gearbox off again, initialize the clutch, mount the fork and on we go with a second attempt to fit the gearbox on the engine.

Initializing the clutch
See 12-16 in the SM. After you've installed the clutch you screw in three small screws (I guess the ones of the cover, well not too long as you have to turn the flywheel for this procedure) in the flywheel from the engine side by hand until they touch. Then you turn the screws by 180 degrees +-30. I recall that if you have done that on one screw the others are very light then. It looked like the mid plate moved parallel to the trans side.

Happy motoring!

[austrian type-r]

Years ago I forgot the fork too, LOL! It's a experience every one has to make it seems. :p

Why did'nt Honda just made a wider hole?! :(

[goldnsx]

Pics for the initialization of the clutch

The M5 bolt drilled in by hand until it touches the midplate.

12853

With a wrench turn 180 degrees. You have to do that on all three bolts. I was wrong you can't use the ones from the cover (M6).
12854

I had to buy M5 but even these were too long. So I had to cut them. Just make sure you that the bolts doesn't interfere with the oil pan.
12855

[goldnsx]

Horray! It's installed (within 30 minutes or so).

12856 12857 12858

I lifted up the engine by about 5 mm and loosened the front engine mounting at little bit more which interfered with the gearbox. Finally it slid it without the effort I had yesterday. Fork installed for sure now. :) Very helpful was the lift with it's fine adjustability until the gearbox is absolutely parallel to the engine. The engine tilts a little bit down. So you have to lift the gearbox the more the closer it gets to the engine.

I already fitted the screws and torque them handtight. Just wondering why the SM wants me to torque them finally after 20 more steps. I was about to torque them right now. Any thoughts on that?

[ozon02]

Intermediate shaft

Pressing out the bearing:

12826 12827

new one in:
12828

new seals and grease and finished:
12829 12830

Intermediate Shaft Bearing is commercially available???

[goldnsx]

I've just ordered the Honda part from their catalog. Bearing plus two seals.

Another topic: in the SM on page 5-29 it says: torque the engine mounting bolts in sequenze shown below. Maybe I'm blind but I don't see a sequence on page 5-29. My idea was to loosen all the central bolts of these four engine mounts, wiggle the engine by hands a little bit and torque them down. Ideas on this?

[Pride]

Pics for the initialization of the clutch

The M5 bolt drilled in by hand until it touches the midplate.

12853

With a wrench turn 180 degrees. You have to do that on all three bolts. I was wrong you can't use the ones from the cover (M6).
12854

I had to buy M5 but even these were too long. So I had to cut them. Just make sure you that the bolts doesn't interfere with the oil pan.
12855

Did you fit a complete OEM clutch kit, if so should it not come with new bolts in the kit for this job??

[goldnsx]

Yes and no. No screws in the new OEM full kit included. :(

[ozon02]

I've just ordered the Honda part from their catalog. Bearing plus two seals.

Another topic: in the SM on page 5-29 it says: torque the engine mounting bolts in sequenze shown below. Maybe I'm blind but I don't see a sequence on page 5-29. My idea was to loosen all the central bolts of these four engine mounts, wiggle the engine by hands a little bit and torque them down. Ideas on this?

I have Acura Service Manuals 1997
page 5-13
"Reinstal the mount bolts/nuts in the folllowing sequence.Failure to follow these procedure may cause excessive noise and vibration, and reduce bushing life.
1.Install the rear mount,then tighten the bolts on the transmission side.Note .Do not tighten the mountig bolt.
2.Install the front mount,then tighten the bolts in the numered sequence as shown.First Bolts front mount (3 pieces) Second mounting bolt (lange)

..........

[goldnsx]

Do you have a scan of that page you can send me or post here?

[ozon02]

I do not see 21107-PR8-000 (https://www.acurapartswarehouse.com/oem/acura%7Ecover%7Erelease%7Ebearing%7Eguide%7E21107-pr8-000.html)

Cover, Release Bearing Guide (https://www.acurapartswarehouse.com/oem/acura%7Ecover%7Erelease%7Ebearing%7Eguide%7E21107-pr8-000.html)?

#41 Photo4

[goldnsx]

I don't have that part on my car.

[Kaz-kzukNA1]

Friction disc balance marking
Unlike 02+ NSX-R, the engine is not balanced with the specific crank shaft/crank pulley/TB drive pulley/flywheel/mid/pressure plates combination so the balance marking on the disc is to distribute the inertia evenly.
Although the crank shaft may look rotating at the steady angular speed at a certain steady rpm, it’s continuously accelerating/decelerating against the time due to the nature of the ancient 4 cycle engine theory.
Addition to acting as the damper when sharp changes in acceleration rate, one of the feature of the torsion spring on the friction discs is to reduce the gear backlash rattling noise from the gearbox when in neutral or under acceleration or steady speed cruising.
So, spreading the inertia evenly will help reducing the potential changes in angular speed.
Thus, you want to set the balance marking on 1st and 2nd friction discs with 180deg offset.

It’s bit too late but when I install the new flywheel, I prefer setting the eng at #1 TDC and set the flywheel triangle marker towards the centre of the rear bank when looked from the gbox side.

This is the method used when doing NSX-R CL service and if you are reusing the flywheel on NSX-R, you must put it back at exactly the same position on the crank end.





Eng/Gbox mounts
From the post on NSX Prime, you already found the answer but in case someone searches this thread in the future, going to post it here. May need removing it for copyright reason.


https://lh3.googleusercontent.com/XnGeO1PYU_tWgg5U8pUqUr47xHURvFW_0P8fdb4fqFRRXD_X0f ZB5tUNQFscZBQu_8GQyUn0QzuDI4rigCvdna5NDu1q5pevGivu EyWrVkN80nifmL2PcXrH4i39oUFA-z2kflYJaIxOgR-S36x0xG2sT_hZ7outjtfhoaZFI27Lh4HFHjagZ-LcIBmq47FQDLIX8J1BzDNc61Pk16Qn2pK4gqZkTZat4hBxHmCB 7FGkedXchCoahapCVQ7PRfDPzZSswDb3vFmW9Ljkmvt2wggPqp 74slOn-_9_1S1JKoiOzL8fQ9A2T7vaOUoBa0s6TXSJsgGfzccA1FqINnk QDUbboplab2rwgoXSFuy-WDlwolyiUdcqV0Ja70Q2vFeaxsVUJO3vzRxjwCegGnlPvZTMDa WTep2YkjuiGRPMYYdM56wTW5kwtDuNwEQGAbhT6NPJ6Za0Rvb8 qaAmKbFtdn7KGChb4-NOsSbIf0GPBm78xJ5dakRFjJkT0B-Y5tgfNDUwiT1vDfHOBmEYbRuGOJtud_nVo8Kq9ljiHW5VsYqAi xykrNx9Y-GPQ-G6tzBqUVtmGCdspnP3HNzHgFezX5aNyL463M9vS2gUb7SN47O4 TSViSIjD5g=w654-h947-nohttps://lh3.googleusercontent.com/DMOMDOQ354CB3EQNkCB7G4wpuEPb9noahBqRbuLj6eYWeDE2tq nyvoeml8qX_V6QNjroPhvJTIg2YMnrsr1QaZw4B9twLDvgtVT2 ghsyXEnoAfVLasIuFQUIziFKr7rCu5Ea6aZGhXtY30-jMA1TF_59xHHCkkEWoeQdVxyIz9P7XEx4N-1C50SSTuWsifeBrXMApz1gWK_eH6BH1MyADTTWw59OKjR42u3_ EF--v_2NUwX4ba9QSvmDZj3lrDXh8Bnko_7orgjBQO3dWmuPkYnFRw 0bKfT1Zj-Mg1lo1wZXNsmy0FEddB-5Eu-6r4DdjHjKAGGmCi_qwx5XD_o8I-kF4LqEPzA2bx1840QikBZxQK4-j64qrKFP_4CJ3_YfTG-F4NEcpVQzj4JunBnGbbt9tiDY0-CGWxyhQqFsXbOou1TXJ9w4bha8jXYMUOFMZKWwKXGPbOSJH7bC fEMgURimnto6aIj_TcP45Z8nDZDxc6rGANdSUZLMkzHzOIjblv HyWmJLqkYlkFu9XJDDsPCYVEPU7jB9kBBIkYNPj5haNoso-LoK3GfmXmY9V1f02wmuSrnnT079WzpWKFGgsLzAVxGy3lEUzx3 axNwqDQSqlvw36g_ZDw=w631-h914-no
All photos courtesy of NSX Wiki on NSX Prime.





Greasing
I now understand the timing you took the photo in post #42.
I normally pack the groove of release bearing with Urea grease and nothing else on remaining area.
Then, I touch the surface of bearing guide with my finger to leave really thin grease film but nothing visible.
I don’t test fit the release bearing once the groove is packed with the grease.

I prefer test fitting the friction discs on the main shaft at different angle, like 10 different alignment.
You don’t need to go through every single spline teeth but this will ensure that you won’t struggle inserting the main shaft when mounting the gbox into the CL set.
For the spline of the discs, not too much grease please but cover every single teeth all the way.
Bit too late but please pay extra attention on greasing the release fork saddle and where the fork meets the release bearing.





Initialisation
Not sure how the CL set was delivered to you but if you pressed on the mid plate before installation to check the guide movement, you should be fine but if not, you may have left tiny gap between the edge of guide and back of the mid plate if you only finger tighten the bolt until it hits the guide and used it as the starting point before further tightening it 180deg.
You probably have enough margin even with the above method but you want to tighten the bolt until the guide touches the back of mid plate and that’s where the starting point before tightening it further.





By the way, from other photo, you’ve done all these with front cross member ( the big grey metal bracket where the front mount centre bolt sits) in place?
Hats off to you if that was the case.
I don't follow the Workshop manual and use different method with cross member out of the way.


Kaz

[goldnsx]

Thanks for your explanation, Kaz.

I'm a technically very curious person and wonder what happens if...that's why I played with the release bearing wondering where the grease goes to when you put it on the guide, esp. when you put on too much. The least thing you want to have is grease on the clutch discs regardless where it comes from. BTW on the input shaft I've distributed the grease with a very soft toothbrush all away round. Same procedure for the splines in the clutch discs. Testfitting and remove all overgrease completely.

the gearbox is now on the car hanging with the engine on all four mounts. The center screws of the four mounts still have to be torqued down in sequence. I've fitted the slave cylinder and shifting cables and sat in the car to check the shifting. Looks fine.

Yes, with the front cross member in place. It's tight in there. A welcome challange for a Swiss precision workmans craft. Thanks to the lift of Asylum you can fully concentrate putting the gearbox on the engine. With a conventional gearbox lift you might have to use 90 % of your force to hold the gearbox and have just 10 % to concentrate on where it has to go. With Asylum's lift it's the other way round.

I have some easier things to complete on the car now. Should be finished over the weekend. Can't wait to start it up the first time.

I was asked why I opened a thread here in the UK forum. Well, while the US forum was my primary source until some years ago there are much more and valuable DIYers in here. Very big thanks to all who helped!

One last question: the SM says to change the set ring on the axle ends before putting the axles in the gearbox. What is the reason behind it? The set ring doesn't look like it needs replacement. And according to the force I had to use to separate the axles from the gearbox I can't think of them going bad.

[ozon02]

Friction disc balance marking
Unlike 02+ NSX-R, the engine is not balanced with the specific crank shaft/crank pulley/TB drive pulley/flywheel/mid/pressure plates combination so the balance marking on the disc is to distribute the inertia evenly.
Although the crank shaft may look rotating at the steady angular speed at a certain steady rpm, it’s continuously accelerating/decelerating against the time due to the nature of the ancient 4 cycle engine theory.
Addition to acting as the damper when sharp changes in acceleration rate, one of the feature of the torsion spring on the friction discs is to reduce the gear backlash rattling noise from the gearbox when in neutral or under acceleration or steady speed cruising.
So, spreading the inertia evenly will help reducing the potential changes in angular speed.
Thus, you want to set the balance marking on 1st and 2nd friction discs with 180deg offset.

It’s bit too late but when I install the new flywheel, I prefer setting the eng at #1 TDC and set the flywheel triangle marker towards the centre of the rear bank when looked from the gbox side.

This is the method used when doing NSX-R CL service and if you are reusing the flywheel on NSX-R, you must put it back at exactly the same position on the crank end.





Eng/Gbox mounts
From the post on NSX Prime, you already found the answer but in case someone searches this thread in the future, going to post it here. May need removing it for copyright reason.


https://lh3.googleusercontent.com/XnGeO1PYU_tWgg5U8pUqUr47xHURvFW_0P8fdb4fqFRRXD_X0f ZB5tUNQFscZBQu_8GQyUn0QzuDI4rigCvdna5NDu1q5pevGivu EyWrVkN80nifmL2PcXrH4i39oUFA-z2kflYJaIxOgR-S36x0xG2sT_hZ7outjtfhoaZFI27Lh4HFHjagZ-LcIBmq47FQDLIX8J1BzDNc61Pk16Qn2pK4gqZkTZat4hBxHmCB 7FGkedXchCoahapCVQ7PRfDPzZSswDb3vFmW9Ljkmvt2wggPqp 74slOn-_9_1S1JKoiOzL8fQ9A2T7vaOUoBa0s6TXSJsgGfzccA1FqINnk QDUbboplab2rwgoXSFuy-WDlwolyiUdcqV0Ja70Q2vFeaxsVUJO3vzRxjwCegGnlPvZTMDa WTep2YkjuiGRPMYYdM56wTW5kwtDuNwEQGAbhT6NPJ6Za0Rvb8 qaAmKbFtdn7KGChb4-NOsSbIf0GPBm78xJ5dakRFjJkT0B-Y5tgfNDUwiT1vDfHOBmEYbRuGOJtud_nVo8Kq9ljiHW5VsYqAi xykrNx9Y-GPQ-G6tzBqUVtmGCdspnP3HNzHgFezX5aNyL463M9vS2gUb7SN47O4 TSViSIjD5g=w654-h947-nohttps://lh3.googleusercontent.com/DMOMDOQ354CB3EQNkCB7G4wpuEPb9noahBqRbuLj6eYWeDE2tq nyvoeml8qX_V6QNjroPhvJTIg2YMnrsr1QaZw4B9twLDvgtVT2 ghsyXEnoAfVLasIuFQUIziFKr7rCu5Ea6aZGhXtY30-jMA1TF_59xHHCkkEWoeQdVxyIz9P7XEx4N-1C50SSTuWsifeBrXMApz1gWK_eH6BH1MyADTTWw59OKjR42u3_ EF--v_2NUwX4ba9QSvmDZj3lrDXh8Bnko_7orgjBQO3dWmuPkYnFRw 0bKfT1Zj-Mg1lo1wZXNsmy0FEddB-5Eu-6r4DdjHjKAGGmCi_qwx5XD_o8I-kF4LqEPzA2bx1840QikBZxQK4-j64qrKFP_4CJ3_YfTG-F4NEcpVQzj4JunBnGbbt9tiDY0-CGWxyhQqFsXbOou1TXJ9w4bha8jXYMUOFMZKWwKXGPbOSJH7bC fEMgURimnto6aIj_TcP45Z8nDZDxc6rGANdSUZLMkzHzOIjblv HyWmJLqkYlkFu9XJDDsPCYVEPU7jB9kBBIkYNPj5haNoso-LoK3GfmXmY9V1f02wmuSrnnT079WzpWKFGgsLzAVxGy3lEUzx3 axNwqDQSqlvw36g_ZDw=w631-h914-no
All photos courtesy of NSX Wiki on NSX Prime.





Greasing
I now understand the timing you took the photo in post #42.
I normally pack the groove of release bearing with Urea grease and nothing else on remaining area.
Then, I touch the surface of bearing guide with my finger to leave really thin grease film but nothing visible.
I don’t test fit the release bearing once the groove is packed with the grease.

I prefer test fitting the friction discs on the main shaft at different angle, like 10 different alignment.
You don’t need to go through every single spline teeth but this will ensure that you won’t struggle inserting the main shaft when mounting the gbox into the CL set.
For the spline of the discs, not too much grease please but cover every single teeth all the way.
Bit too late but please pay extra attention on greasing the release fork saddle and where the fork meets the release bearing.





Initialisation
Not sure how the CL set was delivered to you but if you pressed on the mid plate before installation to check the guide movement, you should be fine but if not, you may have left tiny gap between the edge of guide and back of the mid plate if you only finger tighten the bolt until it hits the guide and used it as the starting point before further tightening it 180deg.
You probably have enough margin even with the above method but you want to tighten the bolt until the guide touches the back of mid plate and that’s where the starting point before tightening it further.





By the way, from other photo, you’ve done all these with front cross member ( the big grey metal bracket where the front mount centre bolt sits) in place?
Hats off to you if that was the case.
I don't follow the Workshop manual and use different method with cross member out of the way.


Kaz





Because they do not know English, if someone could I draw it by hand this " I prefer setting the eng at #1 TDC and set the flywheel triangle marker towards the centre of the rear bank when looked from the gbox side."

[goldnsx]

Because they do not know English, if someone could I draw it by hand this " I prefer setting the eng at #1 TDC and set the flywheel triangle marker towards the centre of the rear bank when looked from the gbox side."

Kaz means this:

12860

The triangle on the flywheel (tri) is facing towards the middle of the rear head (c of rh) WHILE the engine is at #1 TDC (first cylinder).

If my engine was at #TDC (don't know if it was, I guess no) I should have turned the flywheel by 45 degrees clockwise and put the screws in at that position. I was contentrating more at the flywheel run-out but didn't wanted to dissertation about it...

[ozon02]

Hi,
Thank Thomas for help in clarifying. I really appreciate the technical aspects.Like this:
"the balance marking on the disc is to distribute the inertia evenly.
Although the crank shaft may look rotating at the steady angular speed at a certain steady rpm, it’s continuously accelerating/decelerating against the time due to the nature of the ancient 4 cycle engine theory.
Addition to acting as the damper when sharp changes in acceleration rate, one of the feature of the torsion spring on the friction discs is to reduce the gear backlash rattling noise from the gearbox when in neutral or under acceleration or steady speed cruising.
So, spreading the inertia evenly will help reducing the potential changes in angular speed."

Please more .

P.S.I'm working on my English

[nikey22]

I have to agree that this UK website is far superior for DIYs than nsxprime, unbelievable what I've learned here.......

[goldnsx]

Very short testdrive (actually only in front of the house): shifting is fine, clutch is fine, no oil leaks.

Two problems:
- in sharp turns the diff was making some rattling noise I was worried about. The more I drove the quieter it got. The diff was taken apart completly and might needed more oil. I've refilled the gearbox with the old oil and will change to new MTF III after a few km to flush out any dust.
- the backlights are permanently ON. I remember that I've pulled and twisted on the rubber cap when removing it which was not a good idea. But that will be a pretty simple repair. Thanks to the good design of the gearbox you can change it with the oil still in.

[goldnsx]

The weather forecast was too good to postpone the re-registration. So she's back on the road. On an extended 'installation lap' (well, more km than McLaren-Honda usually does in one test day) she drove fine. With a cold gearbox the differential still rattles in sharp U-turns. But it went away when warmed up. I still have to fill in new MTF III and hoping that it goes away forever. Shifting gears was ok/good. I might have to adjust the cables a little bit. Even with being easy on it the clutch smells a little bit, pretty normal.

All the noises went away: 5th gear marbles, input shaft bearing with clutch pedal up.

[ozon02]

Hi,
I think that differential still rattles in sharp U-turns after modification to Type R (more clamping force) for me its normal.
Good that all the noises:5th gear and input shaft went away>

[goldnsx]

It would be interesting to hear more about the stiffer diff from people who did that mod.

[710]

by coincidence I also took my 'box apart last November, we will rebuild it this summer when the parts come in.
Thanks for this thread, goldnsx!!! perfect timing.

Maybe you can tell me, there was a fantastic excellent really good crucial thread about removing and rebuilding the NSX gearbox on either Prime, here, or elsewhere. But I can't find it anymore!!!
By a couple of guys in a freezing garage (their house garage) in the middle of winter.
Probably in the years about 2010 maybe?

I remember it being in Switzerland or southern Germany, but I'm not sure.

I have searched and searched for hours, it seems to have disappeared.
Do you (or anybody else) have an idea where this thread is?

Anyway, thanks for posting this all in detail here.

[710]

gold, I am doing the stiffer diff too.
but wont know anything about it until summer, sorry.

[goldnsx]

The only extensive write-up on the gearbox revision I've ever seen was here on this forum in this thread. The one you are looking for dates back to 2008 done my two people I know :) One of them was complaining about "freezing his a** off" :) Guess who? This was a TB/WP job with the engine out. This was 10 years ago due to some reasons on my side we're not able to do that anymore. Some years later my friend disassembled his gearbox after a track event but I didn't do much pictures of that event. I don't post technical photostories on prime anymore, I prefer this forum.

What's wrong with you gearbox?

2008 story: I guess that nsxprime has lost the story after a few major updates, hard to find now.