DIY: How To Swap a Differential (plenty of pics)

[rwdawg2]

do you know any place where i can get the m3 axles because i have the 3.15lsd i just dont have the axles if anyone knows where i can get the axles i would appreciated it
thanks

[hc1001]

hey tommy, i need to swap the diff cover and was wondering if i could do this while the diff is still on teh car. im assuming i would need to remove the swaybar and drop the exhaust... do u think i can get away with not taking off the diff? thanks.

[phillyB///M3]

hey tommy, i need to swap the diff cover and was wondering if i could do this while the diff is still on teh car. im assuming i would need to remove the swaybar and drop the exhaust... do u think i can get away with not taking off the diff? thanks.

I did this... I cracked my 3:38 diff cover so I replaced it with the one from my 3:15. If I remember correctly: Drain your diff, take off the sway bar, support the diff with a jack, remove the front diff bolt, and also the two rear diff mount bolts, drop it down some to access the top diff. cover bolts, take the cover off, put the other one on and tighten to specs, refill. I think thats all, I might have missed something. I'ts not hard though. Good luck

(might get a little messy)

[old skool]

When I replaced mine I did not remove the exhaust or the rear sway. I unbolted the sway on the one side so I could move it out of the way when necessary. It wasn't bad at all.

[old skool]

as far as the cover goes, first drain the diff using the special BMW tool to open the plug. When you put the new cover on, of course use a new gasket and the sealant they recommend. You should be able to get to the bolts but be careful to torque them in sequence slowly to properly compress the gasket. Buy two new drain plug gaskets.
Then just refill the diff. It is easier to do the cover when it is off but you might be able to do it when it is on.

[phillyB///M3]

yah, now that I think of it.. I dont think I removed the sway either.....

[rwdawg2]

do you know where i can get m3 axles for this lsd swap?
thanks

[Tommy R]

do you know where i can get m3 axles for this lsd swap?
thanks

Why do you want M3 axles? Stock E36 axles will work just fine.

And sorry about not answering about swapping the cover with the diff in the car. As mentioned, it appears to be possible. Sure looks that way...

Tommy

[old skool]

I was going to say the same thing...don't bother changing the half shafts.

[rwdawg2]

no i was swaping my M3 3.15lsd and my stock axles are too small to fit the diff
i have 328is axles and they are too small
i need the M3 axles to complete the swap trust me
so where can i get them

[Tommy R]

And you can't swap the cups (axle outputs) from the old diff to the new one?

Tommy

[hc1001]

thanks all for ur help.

is it safe to drop the diff while its still connected to the axles?

[phillyB///M3]

thanks all for ur help.

is it safe to drop the diff while its still connected to the axles?

I did it... Axle was still connected, drive shaft was still connected... just make sure to support it with a jack.

[old skool]

just swap over the output flanges if the bolt patterns don't line up. I have a 328 and I put an M3 3.23 in there and the axles were fine.

[rwdawg2]

And you can't swap the cups (axle outputs) from the old diff to the new one?

Tommy

dang it i didnt even thank about changing the output shafts
what a wonderful idea withough having to spend even more money
You dont understand how much i appreciate that thanks alot
i will do that this weekend
and again thanks alot

[Tommy R]

That'll be $5, please.

Tommy

[old skool]

Get new seals with lock collars....make sure you have a device to apply even pressure to the seal as you tap it in place with a rubber mallet.

I just swapped them right over.

33 10 7 505 602 2 output flange seal $7.88
33 11 1 211 708 1 cover gasket $3.57
07 11 9 963 355 2 crush washer gasket for drain plug $0.07

don't forget loctite 270 for the diff cover bolts as well as the toquing pattern.

[sportsbum30]

For everybody's info i have to replace a bent control arm and i was removing the axles... i found a set 7 of inverted torx sockets at napa for 25 bucks... it came with something like an E-4 through E-14 and it made an amazing difference... i would recomend the set for anybody messing with the axles.

[hellrot325]

Tommy:

Did my first diff swap and your DIY was invaluable. Thought I would add a few things that I found that might prove helpful to others, especially newbies like me. Used a couple of your pics, hope that's okay:

First, I found you do not need to remove the rear sway bar, although you do have to deal with it. The reason is that it runs directly in front of the two rear mounting bolts and prohibits getting a socket on these bolts. Rather than removing it, I simply removed the two stabilizer supports which allowed me to relocate the bar to remove these bolts. Seemed a much simpler solution than full removal of the bar.

[hellrot325]

Second, once the diff is unbolted you cannot simply lower the diff on a jack as described. The problem is that the front of the diff is over the Rear Axle Carrier, which prohibits lowering. Additionally, the trunk prohibits forward movement. See what I mean?

[hellrot325]

This picture shows the problem of the Rear Axle Carrier and trunk better. I found that you have to rotate the diff out onto the jack, and then lower it and remove. For all those that have done this by themselves, you qualify for "Super Hero" status.

[beatniks325]

glad to see you adding this info to the DIY hellrot325. makes sense to me to do it like you mention in the pics. nice pic too

[hellrot325]

I did not experience the problems you and others encountered in removing the six torx bolts required to connecting the axle to the diff. On mine they were factory connections, and the buggers were tight, but here's what I did.

Because of the angle of the halfshaft to the diff when it is not under load (on jack stands) I found the inner boot prohibited straight access to the torx bolts, except one. This bolt was at the two o'clock poistion on the passenger's side, and ten o'clock on the drivers side. In this position I had easy use of a E12 Torx Socket (from the Sears 3/8 set), with a 6" extension and 16" breaker bar to bust 'em loose, and switched to a ratchet for removal. Use the e-brake or in/out gear technique desribed by Tommy to rotate the axle to get all six of these bolts in the proper position.

Because of the tedious nature of the breaker bar/ratchet technique above, here is a faster way. I put two 12" extensions and one 6" and reached this bolt without having to go under the car. You can access the bolt in the decribed position straight on by running it throught the spring. Even with all the extensions I cold break the bolts loose and quickly spin them off.

I also used this method to reinstall, although I did use the former to fully torque these bolts.

[hellrot325]

One other thing, I added fluid to the new diff before I put it in the car...much easier this way.

All in all the diff swap is not technically difficult, but is a lot of work. Lots of tight and/or rusted bolts. Removal of the exhaust, even with the Tommy R's patented foot method, is work and should be considered a two man job, and if you can get a third, even better!

Thanks for your write up Tommy. Hope these additions prove helpful to others.

[coolcarlski]

Thanks or the write up! I'm about to putin my 3.23lsd.