318ic rear differential interchangeable ?

[Romanianbimmer]

IM in the need of a differential for my 318ic mine is shot. It makes a clunking noise. Will any other model diffs bolt right up? E30s aren't readily available around where I live.if anyone has one for sale or any advice please let me know. Thank you!!! Located in central Arkansas.

[vpilarrt]

Yes, the 6 cylinder diffs will bolt up. They are bigger and heavier but they do fit. Be sure to check the tag on yours so you get the correct ratio.

[hippiester]

isn't the 318 a small case?

[uturn]

My 318is has a small case. Going with the 6 cylinder you'll need the half shafts too. There's one at my local pick and pull. Shipping would cost an arm an a leg.

[Delta]

You don't need the half shafts from a 6 cylinder car to swap diffs, though you may need to swap the axle flanges from your old one to the new. I swapped the small case 4.10 to a medium case 3.91 VLSD (from a 325ix) and it works fine. Junkyard purchase though, and this one isn't prefect either, will be swapping again next year.
Check the new one for leaks too!

[uturn]

Delta is correct, confirmed per realoem, the half shafts are the same on 325's and 318's.

[vpilarrt]

I didn't swap the axle flanges when I installed a 6 cylinder diff in my 318is, has worked fine for 5+ years. How are they different?

[Delta]

I didn't swap the axle flanges when I installed a 6 cylinder diff in my 318is, has worked fine for 5+ years. How are they different?

Not sure they are actually. Can't remember if I swapped mine over or not, I reseated the new diff and had the old one apart at the same time. Maybe I was thinking of the z3 diff or something...

[jeffnhiscars]

You keep the flanges that come with the diff. Small case has a longer flange so in the end the flange faces are all the same distance apart...hence why you don't need to change the half shafts