Author Topic: M3 lsd, what do i need - installed (Read 8149 times)

Berlin · « **on:** May 16, 2006, 03:13:15 AM »

aside from the 4.10 lsd itself (which i already bought) what else do i need to get it to work on my wee 318is... i heard rumors of halfshafts etc, anyone got the facts? thx in advance

-Alex

M42boy · « **Reply #1 on:** May 16, 2006, 09:41:50 AM »

Should bolt right up with no modifications. If not, I've got issues when I reconnect my half-shafts!

Only downside is that the medium case diff weighs 11 lbs more than the small case.
But, at least the weight is in the back and low enough it shouldn't have a huge impact.

Berlin · « **Reply #2 on:** May 17, 2006, 01:30:43 PM »

cool, its just that i heard some ppl saying outrageous things like suspensions changeovers being required to fit a medium case.

what kinda problems fitting the halfshafts? do i need the m3 halfshafts/hubs? anyone else?

M42boy · « **Reply #3 on:** May 17, 2006, 05:13:28 PM »

Well, mine is bolted up, so the rear suspension changeover is hogwash. It has the same mounting points as the small case. Again, I'm almost positive the half-shaft lengths are the same, so you should be able to re-use yours.

I eventually want to upgrade to some "thicker" or more stout 1/2 shafts for later down the road when I drop in an M50 though.

2002maniac · « **Reply #4 on:** May 17, 2006, 11:08:42 PM »

318is halfshafts=M3 halfshafts=325i halfshafts

They are all the same

Berlin · « **Reply #5 on:** May 22, 2006, 12:21:56 AM »

Quote from: 2002maniac

318is halfshafts=M3 halfshafts=325i halfshafts

They are all the same

indeed true, however the driveshafts are not; perhaps the input flanges bolt pattern is different aswell?

2002maniac · « **Reply #6 on:** May 22, 2006, 05:40:01 PM »

The driveshafts are different lengths to fit different transmissions.

Berlin · « **Reply #7 on:** June 06, 2006, 11:02:29 PM »

Ok so i tried to put the new diff in last night. Didnt go quite so smoothly! for some reason it just cant fit into the subframe... after looking closer at them, it appears as though the vertical rib on the input side on the new diff runs higher up than on the old diff, as you can see here:

small case on the left, medium case on the right.

so it doesnt quite fit in the bracket here:

has anyone ever experienced this before?

romkasponka · « **Reply #8 on:** June 07, 2006, 03:11:38 AM »

just drill upper holes closer about 1cm to others holes and it should fit. And check does the bolts screw freely in to differential. After that fit E36 gearbox

tim_s · « **Reply #9 on:** June 07, 2006, 05:07:32 AM »

Quote from: romkasponka

just drill upper holes closer about 1cm to others holes and it should fit. And check does the bolts screw freely in to differential. After that fit E36 gearbox

NO! adjust the collar on the prop to get the prop out of the way, i'd imagine that's what's causing your bolt-up problems. try bolting the diff up without the prop at all first, then try with the prop. the prop will need to be shortened at the collar, please don't drill a perfectly good subframe and throw your thrust angle etc out!

A medium case diff will fit with no drilling subframes required. i have one in mine. nice diff btw, looks lurrvely.

romkasponka · « **Reply #10 on:** June 07, 2006, 05:41:28 AM »

in my situation the distance was different on both differentials mounting holes, and of corse you must check prop shaft travel..

tim_s · « **Reply #11 on:** June 07, 2006, 06:18:39 AM »

oh sorry, didn't realise that, mine wasn't like that! how strange. what is the diff on the right from? i will check part nos on the ETK too see if it has a different subframe, that will confirm everything.

romkasponka · « **Reply #12 on:** June 07, 2006, 06:32:19 AM »

I'm not shure what mine is from M3, it could be from E28 M5 or 535, because rear cover was replaced when I bought it..

zerofreez · « **Reply #13 on:** June 07, 2006, 06:38:22 AM »

I put a medium case diff in my car about 6 months ago, huge pain to get it situated properly in there. Needed a prybar and 2 people to get the last 2 holes to line up properly.

After install I also had some issues with the driveshaft hitting the floorpan about 6 inches forward from the diff. Took us forever to figure out what the banging noise was, only when doing burnouts. I would sound like tire hop going crazy and something in the suspension being loose. We finally saw the marks on the driveshaft and put 1/8" spacers between the diff and the subframe, fixed it compleately.

You should get it to work, Im pulling my 3.73lsd medium case w/ z3 roadster diff cover and putting in a awesome condition 121k mile 4.10 lsd thats never been beat on.

Anyone looking for a 3.73 LSD w/ z3 roadster diff cover, redline fluid used

M42boy · « **Reply #14 on:** June 07, 2006, 10:20:52 AM »

There should be a code/part number on the right side of it stamped into the casing (in case your diff tag is missing). This should tell you what it is, or you should be able to de-code it and tell what it's from.

The M3 diff should work just fine in our cars.