S6-37 6mt swap info (broken off from junk yard thread)

[George Hill]

bigjae46 Obioban

The S6-37 is such a good transmission ESPECIALLY compared to a 420g. I approve of swapping them in place of the 420g. To make the swap you would use everything from the E46 330 setup (clutch/flywheel and shifter). You'd probably need a custom drive shaft to work with the M3 diff though.

IIRC the difference in the M vs Non-M is the input shaft spline count, but I could be wrong.

[bigjae46]

Per BMW, 46kg for the 420g and 43.5kg for the 37BZ:
https://www.realoem.com/bmw/enUS/par...&q=23002229721
https://www.realoem.com/bmw/enUS/par...&q=23007837983

So, 5.5 lbs. If my trans fails I might go that route, but until that time... probably sticking with the 420g.

I do notice the PN for the Z4M box doesn't include anything other than the Z4... so maybe they used some sort of custom bell housing for the Z4M?

Yeah, not worth a swap but if replacing then a BMW reman would be the route I'd go.

[Obioban]

They used it on the Z4M, so you could probably just copy whatever they did there.

…. I wonder how the weight compares…

Per BMW, 46kg for the 420g and 43.5kg for the 37BZ:
https://www.realoem.com/bmw/enUS/par...&q=23002229721
https://www.realoem.com/bmw/enUS/par...&q=23007837983

So, 5.5 lbs. If my trans fails I might go that route, but until that time... probably sticking with the 420g.

I do notice the PN for the Z4M box doesn't include anything other than the Z4... so maybe they used some sort of custom bell housing for the Z4M?

[Obioban]

The ZF 6 speed in the non-Ms shift far better than the rubbery 420g. I think the input shaft is slightly shorter...so would it bolt onto an S54 with the non-M flywheel?

They used it on the Z4M, so you could probably just copy whatever they did there.

…. I wonder how the weight compares…

[bigjae46]

A ZHP? Now that's a good score! Those transmissions are $$$$.

The ZF 6 speed in the non-Ms shift far better than the rubbery 420g. I think the input shaft is slightly shorter...so would it bolt onto an S54 with the non-M flywheel?

[liam821]

usdmej.... Yes

A ZHP? Now that's a good score! Those transmissions are $$$$.

[George Hill]

usdmej.... Yes