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

[KTL]

Nice of you to add to the DIY Hellrot

Good advice on the tool usage too. Sometimes people try to do things only one way and can have difficulty that way. I remove the axle screws on my 911 the same way you described. There's one "sweet" spot where you can get straight access with the socket. Kinda time consuming, but reduces the risk of stripping a screw head.

Enough people chime in with their experiences, and some threads end up becoming the ultimate thread on how to do something. This thread's one of those threads.

[Tommy R]

Hellrot,

Absolutely no problem! I welcome others' contributions. In the end, it makes future diff swappers' jobs easier. And you're more than welcome to use my pictures here. My only request is that if they're placed elsewhere that proper credit be given.

Yeah, the diff can certainly be swapped without removing the rear sway bar. In fact, I've done it that way......by myself.....and without even dropping the exhaust. It's just much easier and less troublesome to remove it, IMO. It's up to the individual. For me, it was worth the extra few minutes to drop the bar.

The torx bits can be a pain, but not so much so if they're clean. Stripping one would suck! The big issue, as you found out, was access. That's why I had a friend set/release the e-brake at my command so I could rotate the diff to gain proper access to the bolts. Made life much easier. I thought about using several extensions, but didn't want to risk buggering up a bolt head. If it works for you and others, more power to you!

And, yes, the diff has to be rotated upward in order to get out of its cradle and past the spare tire well. I just didn't think it warranted noting.

Tommy

[RacermeX]

Great write up!!!
Thanks for sharing!!

[hellrot325]

Hellrot,
Yeah, the diff can certainly be swapped without removing the rear sway bar. In fact, I've done it that way......by myself.....and without even dropping the exhaust. It's just much easier and less troublesome to remove it, IMO. It's up to the individual. For me, it was worth the extra few minutes to drop the bar.
Tommy

I would definately remove the SB if I was doing the swap myself...but then again I wouldn't even attempt that...not when I have a 27 year old son that owes me big time!

[Tommy R]

LOL... Yeah, it was a pain going it alone. I was very appreciative of the help the second time around!

Tommy

[clumpymold]

I would definately remove the SB if I was doing the swap myself...but then again I wouldn't even attempt that...not when I have a 27 year old son that owes me big time!

Wow, your SON is 27? I thought I was old on this forum and I'm 27. Rock on!

[hellrot325]

Wow, your SON is 27? I thought I was old on this forum and I'm 27. Rock on!

Did I put 27? He's 25, I'm 47...I must have been having a senior moment! He loves BMW's also, he was five when I got my first, a 1984 325e in Delphin (a dark gray) and remembers us driving fast with the stereo blasting. Wasn't a high revver but man that car was a torquey lil motha! Put over 300k miles on it before...well you know...like my mom did with our dog... it lives on farm with a nice family

[Mrmontecristo]

Tommy,
Thanks for taking the time to do this write up. I did an auto to manual conversion and left myself with a 3.91 diff. Great off the line, but obviously not highway friendly. So, I bought a 3.15lsd (from a BFC vendor of course), and following your DIY to the T, managed to do the swap in all of 4 hours! A few observations:
1. The bolts holding the diff in place are 18mm (not something in every tool box, well at least my tool box)
2. This would have been a 10 hour job for a first timer w/o the extra man! So, for those planning on doing this, buy the beer and get your buddy on board.
3. Also for those *thinking about doing this* Don't be intimidated. It's not at all difficult. Just follow Tommy's DIY, and keep things organized.
3. This gave me an opportunity to see how shoddy my now former mechanic's work is. I found that when he did the tranny swap - which involved a new drive shaft - he replaced one of the prop flange bolts with a crappy hardware store bolt! I checked the rest of the install over and found other shortcuts, and less than quality workmanship. The words, "You're fired!" comes to mind....
Anyways, thanks again for the write up and pictures. I couldn't have done this in the time I did and also keep my sanity!
Craig

[hellrot325]

The words, "You're fired!" comes to mind....

don't forget to give him the Trump "Cobra" too

[bigbilly]

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

Amen to that - just be sure to add the fluids with the diff level to prevent overfilling... I put in my 3.46 LSD (from Dan at diffsonline) over the holiday week and aside from a few hurdles replacing the center bearing (tip - get a local driveshaft place to press the old one off and press the new one on) the hardest thing was finding a 14mm allen key to get the plugs off. I got a hex bolt from Grainger but it was too long to use with the diff on the car. A allen key from NAPA did the trick.

After doing the M50 manifold swap, this was not too difficult by comparison. The writeup definitely helped - I used the version from someone's website and wish I'd seen this thread first!

[Mini4x]

In my case, the speedo sensor on the "new" diff was smashed so I replaced it with the one from my original diff.

does the sensor need to matched to the gears?

[Tommy R]

does the sensor need to matched to the gears?

Not to my knowledge. I believe there is only one P/N for it.

Tommy

[hellrot325]

Not to my knowledge. I believe there is only one P/N for it.

Tommy

I believe the sensor measure axle rotations thereby working with any diff...wheel/tires have the only effect

[328ischef]

thanks a LOT!
just made my diff swap much easier
great writeup!
-JoSH

[JETninja]

Hey Hellrot325....which end of the Sway did you undo? Or does it matter...about to tackle this myself in a couple days....

Thanks!

[hellrot325]

Hey Hellrot325....which end of the Sway did you undo? Or does it matter...about to tackle this myself in a couple days....

Thanks!

Look at post 69, you'll see that I did not remove the sway bar. I simply removed the two sway bar support and pulled it doen out of the way. I would recommend this only if someone is helping you remove the diff, and I would recommend that you get help. Wether you do what I did or remove the SB like Tommy R...its heavy and ackward taking it out.

[WeiBCoupeE36]

awesome DIY write up man....definitely makin this a subscribe in my book

[///M LIFE©]

You are the man. I wish I had this when I was swapping my diff, but instead took it to the shop

[WeiBCoupeE36]

You are the man. I wish I had this when I was swapping my diff, but instead took it to the shop

now the question is....what diff do i want.....im still learning tho...

[Tommy R]

You're welcome, guys... Happy to help.

Tommy

[danubo49]

That is one good heck of pictures, Tommy, it is very helpful. though it is a bit too much for me, but Ill try with the help of this thread. B y the way, how are you able to post all these beautiful pics, am trying to post some pictures for some DIY I did, the forums won't let me, I always go beyond the 150KB limit. thnx

[hellrot325]

Make sure they're jpeg...you can thow them into MS Paint and resize them and change format...

[JETninja]

I've got two Teenagers to help me! Just waiting for the new (used) one to show up, need to do some prep work today. I don't look forward to the heavy part, I'm a skinny dude! My boys should be able to help though. Need to fab a better platform for the Jack Head too, it's too damn small....

[328 Power 04]

i did it in 3 hours including jacking car up and setting it right... you don't need to take off sway bar .. just loosen 2 rear-most bolts and lower it down and let output shafts hang on it ... no zip ties needed.... its simple

i did 2.93 to 3.15 LSD on a E36 328is

[Tommy R]

i did it in 3 hours including jacking car up and setting it right... you don't need to take off sway bar .. just loosen 2 rear-most bolts and lower it down and let output shafts hang on it ... no zip ties needed.... its simple

Yup, that's all been covered already in this thread. Personally, I found it easier with the bar removed and with zip ties (having done both ways), but to each his own...

Tommy