AT Driveshaft in MT?

Honcho · 11 November 2019

Searched all over, but no definitive answer.

The service manual states that the Right side driveshaft is the same length for both AT and MT. Is also states that the Left side driveshaft should be set to a different length for AT (20.45 - 20.47 in) or MT (20.22 - 20.24 in). It's a little less than 1/4 of an inch difference. I have seen many threads where folks have stated you can re-use the AT Left shaft, but just to set it to the MT length. Others say they are different and should not be interchanged. Honda has two different part numbers: AT = 42311-SL0-900; MT = 42311-SL0-000

Before I go to all of the trouble rebuilding my AT Left driveshaft, can someone confirm it is ok to use in the MT?

bigdare23 · 11 November 2019

Yes the left AT axle will work with a MT half shaft. I used my original axles with my AT to MT conversion.

*edit* Assuming you're doing a conversion, I used this for the part list.
https://fancy-craft.firebaseapp.com/NSX/report/at-mt/report1.htm

Honcho · 12 November 2019

bigdare23 said:
Yes the left AT axle will work with a MT half shaft. I used my original axles with my AT to MT conversion.

*edit* Assuming you're doing a conversion, I used this for the part list.
https://fancy-craft.firebaseapp.com/NSX/report/at-mt/report1.htm

Thanks! I am doing a full conversion. That fancycraft link has been my bible lol. Though I noticed that his electric connector references do not match the connectors in the US market cars (at least as described in the 1991 service manual). Still, it's been enormously helpful!

Did you set the length of the Left axle to the MT spec when you re-assembled?

NSXBenny · 2 July 2020

Hi Honcho, Any update?

I am on the other way, Can a MT Shaft (left and right) fit an automatic? I am considering the insane shaft and they only have the manual.

Thanks

Honcho · 2 July 2020

NSXBenny said:
Hi Honcho, Any update?

I am on the other way, Can a MT Shaft (left and right) fit an automatic? I am considering the insane shaft and they only have the manual.

Thanks

The AT shaft IS longer than the MT shaft, but both will work in a MT car, though removing and installing the AT shaft in a MT car may be more difficult due to the extra length. I am nearly finished with the refresh of my AT shaft, so i was able to inspect it. I obtained a MT shaft from a 1999 NSX and I will refresh this unit to use in my S Zero car. I will list the rebuilt AT shaft for sale here on Prime. I don't think you can use a MT shaft in an AT car because you may face trouble getting full engagement on the hub splines because the shaft is short- you would have to push in/down the hub to get the splines all the way in, which could cock the CV joint at a bad angle and cause excess heat/wear. It also may mis-align the knuckle and suspension geometry. Too many issues, I think. Maybe others can chime in here, but it seems like a bad idea to me.

NSXBenny · 3 July 2020

Thanks Honcho, I have "knocking" sound when engaging gear and mechanics suggest that it is the drive shaft (may be along side with all the other suspension parts). Will continue to search.

YellowTwinTurbo · 21 August 2024

Honcho said:
The AT shaft IS longer than the MT shaft, but both will work in a MT car, though removing and installing the AT shaft in a MT car may be more difficult due to the extra length. I am nearly finished with the refresh of my AT shaft, so i was able to inspect it. I obtained a MT shaft from a 1999 NSX and I will refresh this unit to use in my S Zero car. I will list the rebuilt AT shaft for sale here on Prime. I don't think you can use a MT shaft in an AT car because you may face trouble getting full engagement on the hub splines because the shaft is short- you would have to push in/down the hub to get the splines all the way in, which could cock the CV joint at a bad angle and cause excess heat/wear. It also may mis-align the knuckle and suspension geometry. Too many issues, I think. Maybe others can chime in here, but it seems like a bad idea to me.

I just did AT to MT and kept the driver side AT driveshaft. Are you saying if I ever need to replace the driver side driveshaft I should still order the AT part# and not the MT driveshaft? Thanks

Honcho · 21 August 2024

YellowTwinTurbo said:
I just did AT to MT and kept the driver side AT driveshaft. Are you saying if I ever need to replace the driver side driveshaft I should still order the AT part# and not the MT driveshaft? Thanks

You should order the MT part because the length will be correct (shorter). However, as noted in my post, the AT shaft will work just fine in a MT car. It can just cause a bit more difficulty fitting the driveshaft between the hub and the differential during installation.

AT Driveshaft in MT?

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