M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: badboypolar on March 04, 2007, 05:20:52 PM

Title: Diff replace
Post by: badboypolar on March 04, 2007, 05:20:52 PM

When replacing the actual diff, is there any special procedures that I need to know about? or can I just put it in?

I'm swapping in a LSD.

Title: Diff replace
Post by: doigal on March 04, 2007, 07:53:59 PM

If its the same size then theres nothing special to do. If its a big case then its different.

Title: Diff replace
Post by: jpod999 on March 04, 2007, 11:20:48 PM

How can you tell the difference?

Title: Diff replace
Post by: badboypolar on March 05, 2007, 11:38:26 AM

I will take pictures of the different diffs. However if the diff is in the case and you don't want to take the housing off you turn the input shaft and hold one side. If it still turns but is very tough to turn it is LSD. If the side you are hold stops spinning and the other side still turns it is open.

Title: Diff replace
Post by: Scumball on March 05, 2007, 12:39:32 PM

Look at the backplate... If you have 6 bolts, it's small case, 8 is medium or large, IIRC.

To do the swap all you need to do is shorten the prop. Either loosen it further up and take in the excess, or hit it with a soft-face hammer until it's moved far enough.

Can you guess which I did? :D

Title: Diff replace
Post by: jpod999 on March 05, 2007, 05:11:19 PM

Next time I am at a junkyard I will be looking for a diff with 6 bolts. :D

Title: Diff replace
Post by: tophertii on March 05, 2007, 10:54:22 PM

LSD is not the determining factor. A small case, stock 318is diff will bolt up no worries.
I just installed a 4:10 LSD out of a 325 vert med case. I tried to installed it twice, it seemed like the drive shaft was too long. The med case is slightly longer than a small. I had to loosen the slip joint on the drive shaft and shorten it by 2cm or so. After than the med case bolted right up.

Title: Diff replace
Post by: Scumball on March 06, 2007, 08:14:25 AM

Isn't that what I said? :D

Title: Diff replace
Post by: tophertii on March 06, 2007, 09:59:21 PM

Almost

Title: Diff replace
Post by: 318isle on March 11, 2007, 11:35:28 PM

Quote from: tophertii;20659

LSD is not the determining factor. A small case, stock 318is diff will bolt up no worries.
I just installed a 4:10 LSD out of a 325 vert med case. I tried to installed it twice, it seemed like the drive shaft was too long. The med case is slightly longer than a small. I had to loosen the slip joint on the drive shaft and shorten it by 2cm or so. After than the med case bolted right up.

Hmmm...strange!
I installed a med. 8 bolt 4.27:1 LSD on my car with an M roady diff cover and had no problems! It wasn't as easy as the small case 4.10:1 LSD I installed, but still no modifications needed.

Title: Diff replace
Post by: gundy318 on March 12, 2007, 08:07:36 AM

do you have the small case layin around still? :)

Title: Diff replace
Post by: badboypolar on March 12, 2007, 08:14:11 AM

yes I do.