I looked through Felix's interchange FAQ, and a bunch of threads here, but didn't find any information about swapping in an FD or RX8 manual transmission into a 1st Gen.

My build will have a TII motor in an '85 GSL-SE chassis. Has anyone done this swap, and if so, what are the issues, gotchas, etc.

I'm assuming I'll need to update my driveshaft to accept the larger diameter tailshaft, but I'm not sure about anything else required.

Any help is much appreciated!

Dave

 

Why not just use a TII transmission?

 

As I understand it, the RX-8 speed sensor is not gear driven. I think the FD would be easier.

 

Couple of reasons for considering a swap.

1. TII transmissions are not very new anymore, and (especially) compared to an RX8 tranny, far more likely to be in a beat up condition. FD transmissions could go either way depending on the PO. There are so many TII (and frankly FB/SA) tranny's for sale where the ad says: "previous owner said it was good when pulled" - I just am not interested in forking out cash and time to put in something that's bad or marginal.

2. Tranny's that come up for sale locally (PacNW) seem to get picked up pretty quickly, so I just want to know what options I have available when I see them come up for sale.

3. I think it'd be great to have a 6 speed.

4. I'm not ruling out a TII tranny, just trying to see if that's the only realistic option, or if an FD/RX8 tranny is just as good a choice if I'm going to do the work anyway.

Dave

 

with either transmission you need a turbo sized front yoke, i believe the length is the same between Rx8 and FD, but i could be wrong.

the FD, it should go in a lot like a T2 trans, you need an FD clutch, as its pull type, not push type. i'm not sure where the shifter ends up, trans mount is custom. the FD speed sensor interchanges with the cable drive from a T2 and probably the 1st gen.

the Rx8. it uses a normal T2 clutch, trans mount will need to be custom. the shifter is further forward, so its fine in an SA chassis. since the Rx8 trans is used in a bunch of cars, you can move the shifter back with stock parts, although i'm not sure which ones (probably miata).

the Rx8 uses the ABS sensors for the speedo, and there is nothing in the trans. so you need to come up with some way to do it. dakota digital does make a box that can take an electronic signal and drive a cable.

it also might be possible to use the miata parts, as that one does have a cable drive speedo.

 

Everything I've read indicates that the RX-8 transmission is made of glass. An FD tranny would be the much better choice between the two, but I'd still look at getting a rebuilt TII transmission first.

 

the Rx8 trans has beefier shafts and things than the Fc/FD trannies. they do have problems shifting and or wear quickly.

the Rx8 is also much closer geared than the 5 speeds, so 6th gear is SHORTER than the FD, so the 6 speed turns MORE RPM on the freeway. 1st is about the same, so the RPM drop between gears is much smaller, which is great when you're racing, because there is a gear for every corner.