Author Topic: Small to Medium Case Differential Swap - Definitive answer? (Read 4825 times)

phredphish · « **on:** January 23, 2008, 07:58:33 PM »

I've searched the posts and can't seem to find a definitive answer. Does a e30 medium case differential bolt in (without modification) to my 1991 m42 318i?

I don't care about ratios or anything else, there is plenty of information on that elsewhere, all I want to know is the answer to my question above.

Thanks,
Andrew

tjts1 · « **Reply #1 on:** January 24, 2008, 04:00:32 PM »

tim_s · « **Reply #2 on:** January 24, 2008, 04:14:31 PM »

mine needed the prop to be shortened on the collar, but yes did fit without any other modification.

gjuuu · « **Reply #3 on:** January 26, 2008, 02:28:47 AM »

I found that I had to slot the top two holes in the subframe by approx 5mm.
You can sort of see the difference in this photo - I tried to highlight the difference the best I could.

This could be for numerous reasons - my car is a 1991 and the diff is from a really early e30.
But having said that it was no big deal - just frustrating as the bolts just wouldn't line up no matter what I tried

romkasponka · « **Reply #4 on:** January 26, 2008, 03:23:55 AM »

The same was with mine swap. But as I know my dif was from E28 and just rear cover was replaced.. I think housing is the same like yours..

twinpop171 · « **Reply #5 on:** January 26, 2008, 05:19:59 AM »

Yes.
I recently did this swap. I also swapped the half shafts from the donor car. They are a little shorter than the small case shafts iirc. Mine bolted right in but it was a bit of a PITA to get the bolts started.
Good luck, Dan.

Wizard · « **Reply #6 on:** January 27, 2008, 07:40:56 AM »

Also did this swap last summer-4.10 small case to 4.10 LSD medium case....Nothing else was swapped out and fit perfect.

Dan

DZick · « **Reply #7 on:** January 31, 2008, 08:38:43 PM »

Quote from: gjuuu;41724

I found that I had to slot the top two holes in the subframe by approx 5mm.
You can sort of see the difference in this photo - I tried to highlight the difference the best I could.

This could be for numerous reasons - my car is a 1991 and the diff is from a really early e30.
But having said that it was no big deal - just frustrating as the bolts just wouldn't line up no matter what I tried

Same