Author Topic: 4.10 LSD fitment issues (Read 4327 times)

Nick_318is · « **on:** March 18, 2008, 05:32:34 PM »

Hey guys I recently bought a 4.10 lsd in what I believe is a medium case. When going to install it I have found that it will not bolt up properly much to my surprise. Can anyone tell me if you need a certain case in the 91 318is to make this work or if I was mislead, is this not a direct bolt in on the m42 cars? Here are some pics showing the problem and new vs old-open (on the right). I'm trying to figure this out before I spend more money on finding another LSD. I'm also guessing that the gears in the bigger case won't work in the small case? Thanks for the help. If anyone wants the diff send me an offer.
Side by Side:

Bolted to the driveshaft:

Wizard · « **Reply #1 on:** March 18, 2008, 05:38:09 PM »

You might just to have to give the end of the driveshaft a "whack" to move it forward the slight bit needed. I changed my small case to med case and had to do that....Everything will line up and work fine after that.

(P.S.---Use a block of wood)

tjts1 · « **Reply #2 on:** March 18, 2008, 05:44:00 PM »

The drive shaft is adjustable for length. Try again.

Nick_318is · « **Reply #3 on:** March 18, 2008, 06:04:44 PM »

Really thats good news, I will let you know if this works out or not.

sumyungguy · « **Reply #4 on:** March 18, 2008, 11:33:27 PM »

I was wondering what happened to you, glad to see your finally getting around to put that diff in.

Yeah you have to slide your drive shaft in a little..

BTW is your small case a LSD? If so, Im interested...

strypt · « **Reply #5 on:** March 19, 2008, 03:56:08 AM »

As mentioned you have to slide your drive shaft in a bit but rather than giving it a good whack try loosen the nut on the middle of the shaft (where the slip is) and it should go in without much force.

Nick_318is · « **Reply #6 on:** March 19, 2008, 04:04:10 PM »

The car was in the garage all winter and now that its getting nicer work is getting done. The Small case is open otherwise I wouldn't be worrying about at swap at this point. I will let you guys know what I hear as I'm having a bit of work done on the car at the moment so i'm letting someone else deal with this. I was just concerned when they let me know it wasn't fitting and showed me some pictures.

ajajliardo · « **Reply #7 on:** March 20, 2008, 07:04:07 AM »

So, are there any other issues when swapping from a small case to a med case? Do you need to change the axles or output flanges? I'd like to swap my 4:10 open in my 318i to a 3:73 lsd to pick up some traction and mpgs.

Nick_318is · « **Reply #8 on:** March 21, 2008, 10:06:04 AM »

Thanks for the help guys with what you told me and I relayed on, they got the diff mounted no problem and say everything is still within BMW stock tolerances, I think I get the car back next monday, hopefully the snow we are supposed to get leaves quickly so I can drive this thing again.

The car is also getting the ie 22/19 sways, m3 offset bushings, new control arms and tie-rods, new bilstein sports all around, a complete tune up and fresh fluids, a more aggressive alignment for the track, and anything else that is wrong is getting fixed. Should be even more of a handling monster! Next, I'm going to need to figure out how to get some power out of it.

enildeR · « **Reply #9 on:** March 23, 2008, 03:43:23 PM »

Where did you buy the unit from? I've been interested in getting a med sized rear case. How much was it?

You know they have a supercharger kit for our cars now, right?

Nick_318is · « **Reply #10 on:** March 24, 2008, 07:06:28 AM »

I know of grassroots problem and its in my mind as something to do. I bought the diff used probably off of this site or from e30tech, i don't remember exactly where. They used to pop up all the time but i have seen a lot less lately.

Wizard · « **Reply #11 on:** March 24, 2008, 05:55:18 PM »

enildeR,
Sometimes they pop up here, R3V, Bimmerforums...Also check ebay---but they are usually pretty expensive. Sometimes you can find them in junkyards also, but the problem there is you might have to climb under the car to check the tag on the diff to be sure of the ratio. I am not sure if the junk yard could run the VIN to get the info on the spot. Expect to pay in the neighborhood of $300 for a good LSD.

Wise Old Dog · « **Reply #12 on:** March 24, 2008, 06:08:51 PM »

That 4.10 is going to be hard to find in a medium case. Most are 3.73. Check out diffsonline.com , they have parts to rebuild the medium case, and maybe even change your gear to exactly what you want.

enildeR · « **Reply #13 on:** March 25, 2008, 10:56:10 AM »

Thanks!