non-interchange transmissions

[Jason89i]

This is the first pre facelift e30 ive ever worked on. we were replacing the transmission out of an 86 325es (m50) with a trans out of an 89. I assumed the drive train parts were the same. They are not.

1. the getrag bell housing is longer (about 3/8" longer from slave to mounting) on the “es” to accommodate the dual mass flywheel. So when replacing flywheel with single mass, you need a 323i throwout or modify (lengthen) the “I” one. The flywheel / transmissions are not interchangeable.
2. the guibo’s are larger diameter and different bolt pattern on the “es”. Yes, that means the transmission output shaft, guibo and driveshafts are not interchangeable between “e” and “I”.
3. the mounting holes for the center support bearing are farther apart on the “es.” The “I’ support bearing will not mount into the “es” holes.

cheers, jason

[trent]

This is the first pre facelift e30 ive ever worked on. we were replacing the transmission out of an 86 325es (m50) with a trans out of an 89. I assumed the drive train parts were the same. They are not.

1. the getrag bell housing is longer (about 3/8" longer from slave to mounting) on the “es” to accommodate the dual mass flywheel. So when replacing flywheel with single mass, you need a 323i throwout or modify (lengthen) the “I” one. The flywheel / transmissions are not interchangeable.
2. the guibo’s are larger diameter and different bolt pattern on the “es”. Yes, that means the transmission output shaft, guibo and driveshafts are not interchangeable between “e” and “I”.
3. the mounting holes for the center support bearing are farther apart on the “es.” The “I’ support bearing will not mount into the “es” holes.

cheers, jason

When I did the conversion into my 84 318, I used everything from my '89 M20 325. This did include having to switch the center bearing to the earlier style.

[matt]

That's not 100% accurate. Some etas have small guibos, some have large.

There are definitely clutch/flywheel combos that fit some gearboxes and not others. An M3 JB racing flywheel and an OE clutch fit great inside an eta gearbox... but don't fit at all within an e36 318i gearbox. They do fit in an e36 325i box.

[raimo]

about the guibos

There are two types of guibos, 110mm and 135mm. the bolt-holes are 78mm vs 96mm. the driveshafts are different also.

in europe
a 325i(s) has always a small guibo
a 324td has always a big guibo (where there any diesels in US ?)
a 325e(s) has a big guibo starting 03/1986

[Jason89i]

also, shift linkage / imput shaft knuckle is different. had to swap pivot knuckle on selector shaft.

VERY helpful replies. thanks.

after owning a dozen e30's (and working on a lot more) im constantly amazed at how different each car is.

cheers, jason