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1991 Auto to Manual conversion question

31 January 2008
Wellington, New Zealand
I am hoping someone who has done this before or is a parts guru will make my question very easy to answer......

Some background. We purchased a 1991 NSX auto to use as the base for our racecar. We had a 5 speed manual box we had purchased from the USA and was told that it was a straight swap out alignment wise for the auto.

Once we swapped the gearbox out it was all good, but then we went to put the right side driveshaft in and it wouldn't reach the gearbox and was out by about 20mm or more from where it needed to be. Then I looked at the drive shaft support hanger that comes straight off the engine block and it had AT stamped in it. Assuming this related to Automatic Transmission, I enquired and found out there was in fact a manual version and automatic version of this bracket so we sourced a manual one and fitted it.

It seemed to work, however once we filled the gearbox with oil (brand new seals all through) we had a major leak through the right side seal. It turns out with more investigation that although the driveshaft looks like it fits, it is in fact about 5mm, maybe 10mm short of actually sealing properly. The driveshaft literally touches the edge of the seal, but doesn't reach inside it to actually seal and this is where the leak is coming from !!

So my question is............ is there a difference between the right side driveshaft on manual and automatic cars ??? We assume so given what I've described above, but it would be good to know for sure so I know what I need to source to resolve the issue..........

If there is in fact no known difference between the cars then we're going to have to do some more hunting to try and figure out how we have ended up at this point....... !!

Any help is much appreciated ! This is now the only issue holding us up from tuning the thing so it's a bit annoying if I have been given bung advice !
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I'm no expert, but the OEM parts catalogs call for the same driveshaft assembly (part number 42310-SL0-000) for AT and MT cars.
At least one of the drive shaft is different. I have done the exact conversion for my JDM 1991 from AT to MT. I will double check my noted and let you know.

The best thing about this conversion is that you get to keep the EPS but you need to add a washer to one of the sensors attached to the MT gearbox.
Where did you send it ?? Haven't got anything ......

My conversion is done, I just need to know if the driveshaft I have is the correct one and the issue is somewhere else, or if the driveshaft I have is the wrong one and that's why we are short........

Once I know that then we can fix things from there :)

** EDIT ** It just showed up.
I just did the same conversion on my Reventon Nsx and had the same problem! Left and right driveshafts are exactly the same for MT or AT cars, however the intermediate shaft is not, neither its support. I also tried to replace only the suport as it was the only part with the AT mark, but the intermediate shaft is 5mm shorter for the AT. You need to find yourself a real MT one
You will also need to fit the clutch oil line going from the master to slave clutch cilinders, the clutch pedal, the gearbox shifter cables and supports...
For the harness I replaced the complete AT one for a MT one, to avoid electric problems as AT TCS module wiring, gearbox speedsensor? and so on..
For the engine, the cams are different from MT to AT and probably some other parts or vaccum lines so to be easier I decided to replace the complete engine, i sold the AT and bought an MT one
Good luck on your conversion