Automatic gearbox problem

[NorwayNick]

Hi the NSX from 91 i have will not select reverse gear when selected, but seems ok in all forward gears, any ideas on what my problem might be.

This is an Automatic transmition

thanks Nick

[NSXGB]

Have you checked your fluid level lately?

[NorwayNick]

Yes seems to be ok

[NSXGB]

How old is the fluid? When was the filter last changed.
Hopefully Kaz or Britlube will chime in because I don't know much about autos as you can tell!

[unclebob]

sounds like one ogf the solenoids, possibly?

[NSXGB]

I presume the auto transmission has the ability to throw error codes in certain circumstances? In which case, it would be worth retrieving these. If you don't know how to do this, a quick search I here or prime will get you that info.
If you list the year of your car too it may be useful for reference.

[Kaz-kzukNA1]

As always, extra information will help us on supporting you.


For example, what was the mileage of your NSX when the issue happened?


Any modification to the engine, header, ECU, etc?


Did you experience this issue all of a sudden or any symptoms that may lead to this in the past?
When you were able to select Reverse in the past, did you feel anything strange or had difficulty in selecting Reverse but managed in the end previously?


Any history of service work around the area of AT shift lever as well as on the selector cables?


How is your speedometer?
Have you seen your speedo suddenly jumping around randomly or dropping to zero while you are driving?


As NSXGB mentioned, did you see flashing green ‘D’ indicator?
It indicates the failure on AT system.

Please check the error code even if you think you didn’t see the flashing ‘D’.
Please follow this link for the procedure;
http://www.nsxcb.co.uk/showthread.php?9229-How-to-read-the-error-code...&p=85855#post85855

With some of the AT failure mode, the error codes are not stored in the memory once you have switched off the engine so you need to be bit careful with this..


How did you check the ATF level?
You must check it as soon as you shut down the engine otherwise the fluid level on the dip stick will go up and lead to the wrong information.


What was the colour of your ATF?
Clear bright Red, dark Red or close to black?

Enough as a starter….


Kaz

[A.S. Motorsport]

Like posted up before,

Check for transmission Cell (in your transmission light cluster)
Check transmission fluid make sure it has Honda ATF!
I know the Honda ATF is pricey but it's well worth it makes a big difference for the transmission.

Possible cause that rings a bell would be solenoid older automatic transmissions from Honda often have that as a problem just as incorrect fluids.
VSS sensor causing lock out of your reverse could also be a problem.
Control cables like Kaz pointed out.

Also how is it shifting under heavy acceleration?

[NorwayNick]

ok the car has a stock engine and has covered 80560km or around 50000 miles, the gearbox seems to work in all forward gears but not in revers.
There is a clicking sound from the gearbox as you select R but it does not make any effort to move.
I have drained and refilled the gearbox with Honda Automatic trans fruid and it has had no effect.

The Lights on the Geabox selector indicator is steady green and does not flash

this happend suddenly no previous problems with the gearbox or selecting rev, the car has had no work done around the gearbox and i have checked to see that the selector cable is ok.

i will take the car out now to see if there is anything else strange that i have not checked for

thanks Nick

[NorwayNick]

ok been out for test drive, speedo does not jump around, when in drive and the car is warm if you cruse without foot on gas then accelarate gentle the box feels like it selects neutral then if you push and reach the kick down point it engages and drives ok. The car seems to drive fine if you select 1,2,3 manually.
No nasty sounds coming from the box but nothing happens when you select rev