Midcase 4.10 LSD differential fitment issue into a BMW 318iS

[Weeman83]

Hi all,

I am having issues fitting a midcase 4.10 LSD diff into my 318iS. It came off an 89 325i Auto. As far as I know, this is not an uncommon swap!

The curious thing is, it didn't completely not fit. It is missing the bolt holes by perhaps a 1/16" of an inch - and I measured the bolt pattern against my small-case diff and they turned out to be the same.

Apparently I need to shorten the driveshaft a bit to fit the bigger diff, but I seemed to have ran out splines on the driveshaft for length adjustibility, with about 1/16" left making all my bolt holes not line up.

Any insights? Thanks

Linc

PS: RealOEM shows the subframe of my 318 with that of an 89 Auto to be the same P/N, so if RealOEM is correct, the subframe shouldn't be the cause of the misfit!

[rkettner]

if you are replacing the diff with your subframe still in the car then i can feel your pain. worse yet if you are doing it on jacks stands.

my bet is that it will fit with enough manipulation, aggression. having just done my diff on sunday i completely understand the different axis, spacing, threads etc that are all a pain.

[craig4ie]

Originally Posted by rkettner if you are replacing the diff with your subframe still in the car then i can feel your pain. worse yet if you are doing it on jacks stands. my bet is that it will fit with enough manipulation, aggression.

Ya, just keep fighting with it and eventually it'll pop in. If you're really concerned, measure the the distance from the forward bolt holes to the face of the shaft that connects to the driveshaft and compare it to your old diff.

but ya, 1/16th...just keep fighting...you need a bigger hammer

[jenifer.kaif]

Its better to go to the car body shop and get it repaired.