Upgrading to LSD diff

[Coyote_ar]

So, a friend was parting out a 535i (VIN 2894694), and it had an LSD diff so i got it. Initially we though we could just remove my open diff and drop in that one. But when we removed the diff, we noticed that my current diff was smaller than the one from the 535i. I wasnt expecting that, so we compared them. The one from the 535i had bigger halfshaft output flanges (and they wouldnt swap with the ones from my car), and the input for the drive shaft was different as well. Could this be a 210mm diff? I has a big 7 on the side of the casting (seen on the 1st photo below).
http://i64.tinypic.com/riu543.jpg
http://i66.tinypic.com/14cse80.jpg

I ended up buying drive shaft, diff and halfshafts. we tried the halfshafts on my rear end, and they do fit. So basically diff + halfshafts was good. Now the last bit is the driveshaft. I searched in realoem, and found that the 535i had 3 different parts (2 with same length, and the most common is shorter. im guessing thats the one i got since car isnt from australia/japan, need to measure that up.) ... anyone knows what determines the difference?
http://www.realoem.com/bmw/enUS/showparts?id=HD21-EUR-09-1988-E34-BMW-535i&diagId=26_0021

http://i65.tinypic.com/11m6x5e.jpg

This is the one i currently have installed, but i dont know how long it is (i would rather find out online how long it is, rather than having to remove it to measure).
http://www.realoem.com/bmw/enUS/showparts?id=HC21-EUR-11-1988-E34-BMW-525i&diagId=26_0021

I need to tidy up the one from the 535i before i put it in, so i would prefer to be sure its the length i need before doing that.

In case length is a problem, is it possible to make a hybrid using the front of my current driveshaft with the rear of the 535 so it matches the diff input?

[632 Regal]

is it possible to make a hybrid using the front of my current driveshaft with the rear of the 535 so it matches the diff input?

Have to have it balanced if you mix n match.

I'm not following, you say this dif was from a 535 (a 535) what year? And what year is the car your putting it into? Too much info missing here. You should have been able to pop the side flanges off and swap them. The input flange should have been swapped (careful with the preload). I dont know why one case would be bigger than the other. As I said more info needed.

[Coyote_ar]

Sorry i linked the realoem info for that car and the VIN.

The 535i is from 1988 (VIN 2894694). My 525i is also from 1988 (VIN 4237760).

My initial belief was as you said, that both cars being a 6cyl they should have the same 188mm sized diff. When we removed the one from the 535i and compared it with the one from my 525i. The size was considerably bigger (and heavier). We removed the side flanges, and the one from the 535i was quite bigger. The splined shaft that goes into the diff core, was almost 1cm thicker than the one from my car. I've noticed that on the side of the 525i diff, there are 6 bolts on the cover next to the side flange. But on the 535i diff it has 8.

This is the one i currently have on my 525i
http://i65.tinypic.com/xdjyp.jpg

I found online a side by side comparison of a 188mm diff and a 210mm diff, and the one from the 535i seems to be a 210mm ...

http://i232.photobucket.com/albums/ee21/me6j/874bc5ab.jpg

why this 535i had this diff? i dont know cause AFAIK those 210mm diff only came in V8s and M5, right?
the ratio for the 535i diff is 3,64:1 as per the tag on the side.

As for matching the driveshaft using parts from both i got, having it balanced is no problem. I was planning on doing that even if i dont mix parts anyway. But do you know if the splined shaft that connects the front and back halfs is the same size for all E34's driveshafts?

[632 Regal]

All right I gotcha. The 525 has the smallest diff of all E34s. The largest diffs are on the 540 and M series. Everything other than this is the same as the new one you have including the V8 530.

I have a 3:64 and when I got it nobody had a clue why the flanges were different as it was supposed to be plug n play on my 94 530. When I transfered it to my 95 530 the input flange was different and the driveshaft was smaller. Just something they did I guess.

That being said, your 525 driveshaft may be smaller in diameter than the 535. As long as you can bolt it to the guibo it should fit right in.

[Coyote_ar]

Both cars had a 4HP22, are there 4 bolt and 3 bolt guibos for the same trans? or all 4HP22s had the same 4 bolt thing?

[632 Regal]

Far as I know they should all have the 3 bolt per side.

[Coyote_ar]

it looks like the 4 bolt one doesnt use a guibo, it just bolts on to the trans.