Bought 3.15 LSD but ...
 

So, picked up a 60k mile 3.15 LSD from a March 1998 build Z3 2.8 this morning and couldn't wait to pry the thing open on the drive home ...

Got home and opened it up to find ...

http://photos-f.ak.instagram.com/hph...22134521_n.jpg

... it's a Clutch Pack and not the Torsen that I was looking for. Thought I was pushing it with a 1998 Z3 as I had read either 1) that all 6-cylinder Z3s had a Torsen or 2) that they began in 1999. Should've done my homework. Gambled and lost. Sigh. Part of me wants to just keep the diff and move on with my life but I was really looking for a Torsen and I don't want to swap diffs again down the road.

It's also worrying me that I can easily spin the flanges in opposite directions by hand ... does that mean i need to rebuild or will it not lock up if it's drained / not on the car?

Any help appreciated.

Just do an easy rebuild to the 3 clutch and you will be happy. From what I understand, probably happier than you would be with the torsen. I am installing a torsen diff into my swapped ti but when a medium case LSD in the right ratio falls into my hands I will go with that.

Don't feel like you lost, you still got a great diff.

Have asked around a bit and I'll probably stick with the clutch-type LSD ... can always rebuild / refresh down the road and the trouble to go get a Torsen is just more than I want to do right now.

Couple more questions though:

- When I spin one side, the opposite side spins with it. Means I have an LSD. Good news. However, when I hold both flanges and spin one of them, I can easily hold the opposite side in place or even spin it in the opposite direction. Does this mean I've got a dud / need to rebuild?

- Looking to buy some E30 M3 halfshafts and wanted to make sure the flanges from my 2.8L Z3 diff will mate up to the new halfshafts ... Will I be able to keep Z3 output flanges for use with the E30 halfshafts?

I had to swap out my z3 output flanges for e30 ones in order to use them with e30 halfshafts.

This is a great write up on doing a stock 2 clutch refresh. The 2.1mm dog ear plates give you a little more bite than the 2.0mm. However, the most popular refresh is the 3 disk with 3 2.1mm plates. To do this you can remove the bottom spacer and insert 3rd disk/plate giving you 40% lock up. Check it out:

http://www.mye28.com/viewtopic.php?f=9&t=93418

A rebuild will never be more convenient than right now, before you put the diff in. I would not be surprised to see heavy wear on the clutch discs and the dog ear plates.

Yeah, most say to just flip the dog ear plates and put in new clutch disks.

If you're going to rebuild just get new dog ear plates. The plates wear down and can make the LSD less effective, they are machined to tight tolerances for a reason.

bimmerdiffs.com has all the parts you need and Jonathan is very knowledgeable. I've rebuilt two diffs using his parts and they've been awesome for Autox/track work.

I agree 100%. Rebuilding a diff is a lot of work. Skimping on internal parts once inside is false economy.

Needs to be rebuilt. Clutches are worn and they are already slipping. There should be resistance and not be able to spin it in the opposite direction.

Ok - Resurrecting / somewhat changing the subject but wondering on halfshaft-to-diff bolts. Seems that the hex bolts provided with halfshafts are too long. Thinking that these bolts that are specific to my 2.8L Z3 diff might do the trick?

http://www.ecstuning.com/BMW-Z3-2.8-...Axles/ES56839/

Any help appreciated.