Diff swap e32 into e24

[GazM3]

Hey chaps.

Today has been a good day. Finally got my e24 back on the road since December last year. Mechanic suffered a breakdown so I’ve had to manage car projects directly which takes more time. Retrofitted the 25mm master from 750il, installed new fuel pump, and restored the fuel interceptor computer. It’s good to just drive it again finally.

Anyway. Enough sulking.

My m635csi now runs a dogleg gearbox with a medium case e34 diff running 3.46:1 ratio as the original 3.73 diff was too short. The lsd unit is starting to be ineffective and was contemplating going slighly taller.

I have a spare 3.15:1 e32 750il lsd diff in good condition. I also have my original e24 back plate. This ratio would seem ideal with the dogleg and give me about 2700 rpm @ 100kmh instead of 2950. A big difference is at 160kmh I’ll be doing only about 4300rpm rather than a buzzy 4700. I do also have a set of 3.23:1 large case gearset but it would require opening up the diff and retrofitting the gears. It’s still pretty short geared.

Will the large case fit. (Original diff was 3.73 e24 large case now in my e23)?