Originally Posted by rider-.
I actually just stepped in from my garage while doing this same swap. you have to use the m3 driveshaft since the diff is longer on the m3. so the diff to center bearing will remain unchanged from the rear end. and then you have to get the front end of the driveshaft modified for your 5 speed tranny since it is shorter then the m3 tranny. ALSO! and i just made this mistake and I am furious because of it. The flange on the 6 speed bmw trannys is different then the output flange on the 5 speed trannys. It is larger. therefore when you are getting the driveshaft customized, u must also transfer the flange off the 5 speed driveshaft to make it work. I just spent hundreds of dollars on customizing my driveshaft and made this mistake.
little bit of a threadjack but it will come to your benefit knowing aswell possibly, but would the m3 transmission output flange bolt onto the 5 speed because I know it is held in by 1 bolt, the only reason I havent gone forward and checked is because I do not want to bother sourcing the flange if it might not work. the shaft coming out of the flanges are the same, but is the shaft inside the transmission actually the same. If anyone could answer this that would be VERY greatly appreciated.
The tranny output flange teeth should be the same on both 6spd and 5spd, so technically it should bolt on. But I don't wanna do all that custom shit with the driveshaft it's too much money, i wanna find on that already fit as it is, assemble it from two pieces and thats it. I'm still doing trial and error as soon as i come up with something that works i'll post it up.
1990 M5 Euro
You wash your car like it was your firstborn child, you tend to its needs like it was your own body, you protect it like it's your family, then you drive it like you stole it