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

[DBK81]

So can anyone confirm the torque specs from the Bently Manual on the input and output shafts? I am doing this swap next week and will need them. Thanks.

[angeleus]

here ya go from the Bentley:
Driveshaft to final drive flange:
Final drive input shaft flange to pinion with 4 bolt side covers: 129 ft-lb
Final drive input shaft flange to pinion with 6 bolt side covers: 137 ft-lb

Drive axle to final drive flange:
M8 Torx bolt - 47 ft-lb
M10 Torx bolt - 74 ft-lb

[DBK81]

Sweet that's the best! Thanks so much.

[angeleus]

you're welcome! Good luck. I can't wait to install mine this weekend!

[Lohe]

here ya go missing most the pics but still has the wording.

http://web.archive.org/web/200504211.../lsrepair.html

[yamhill]

You can gain a lot of access by removing the middle two sway bar mounts and leaving the ends attached. The bar will pivot on the end points and you can get it out of your way. Just loosen two easy access bolts and swing it down.

[das borgen]

sorry for the bump but....
Awesome thread is awesome

[Schnell325]

You can gain a lot of access by removing the middle two sway bar mounts and leaving the ends attached. The bar will pivot on the end points and you can get it out of your way. Just loosen two easy access bolts and swing it down.

Exactly what I did. Works great!

[Djtreson]

i would like to swap my 318is diff to something stronger due to my 2jz swap i dont wanna break down doing just burnouts any suggestions on any affordable diffs............

[pomps325i]

Just did this today and what a PITA! Everything that could have gone wrong did go wrong. Took forever to get the old one out and once it was out, filled the new one up with Redline 75w90, put it in and realized that the axel flanges (output flanges I'm guessing) didn't meet up with the axel. So back out it came, at this point I'm like f*** me. A buddy of the guy that did the install for me made a call and said the output flanges are interchangable, so we swapped those and back in it went. Only thing we forgot in the end was to connect the speed sensor but that was an easy fix!

If your gonna tackle this yourself, make sure you start early in the day as it will take longer then expected, then again anything with cars does. Make sure you stay calm cool and collected so you don't freak out like me. And thirdly and probably most importantly, have lots of beer cold and ready to go, your gonna need it!

[HeartBMW]

Such a good write up. Wish all DIY write ups were like this. The only thing I could request is maybe an inventory checklist of tool and other things you need to do the job so I could see everything in a quick list. I hate starting a job thinking you've got everything for it then realizing you've forgotten something crucial for the job.

[ecastpro]

I recently swapped mine but the driveshaft wouldnt reach the diff! Anyways, since its impossible to find the measurements for the driveshafts to see if that was the problem...I found out realoem has the exact measurements in mm on there.

[MCSaints72]

I know this thread is old but i have a question: I thought that when you swapped an M3 dif to a 325 you had to change something? Is that not actually the case?

[Bowze]

I know this thread is old but i have a question: I thought that when you swapped an M3 dif to a 325 you had to change something? Is that not actually the case?

U may have to change the output flanges over from the old diff into the new, that's what I had to do.
But since they just pop out it took all of 5 minutes

[MCSaints72]

U may have to change the output flanges over from the old diff into the new, that's what I had to do.
But since they just pop out it took all of 5 minutes

But nothing with the input? I also thought the M3 had a bigger did case

[flyfishvt]

Europe got the m3's with a large case dif. All 323 325 328 and m3 in the US got a medium case dif

[MCSaints72]

Oh ok, that makes things a lot easier then

[Franky goes]

Thanks to the OP for starting this great thread.
It was very helpfull to me when I upgraded to a race diff with Rogue cover.
Here is my contribution.

With the Rogue engineering cover and the aftermarket Hotchkis sway bar in the back you have to remove the bar completely. You also have to bang in the spare tire wheel well by a couple of inches to install the bar pass the oversized Rogue finned cover.

The M10 half shaft bolts are specified at 74 ft-lb but the instructions from Rogue Engineering that came with the cover specify 50 to 60 ft-lb. Honestly I did not feel comfortable tightening these at 74. Just felt wrong. So I now have them at 55 ft-lb.

This is on an M3 so the rear discs are vented.
I use an allan key jammed in the break calipers / disk vents to loosen and tighten all the bolts. Much faster than using the hand brake from inside the car.

For reference I now have done this job twice, on a lift, without removing the muffler and with a helper. First time was 6 hours. Second time was 3 1/2 hours.

[asandrewsilva2]

Wow that's the best DIY on differential swapping I have ever seen! I think its time i give it a try myself, though i need to get a LSD first. ( =^w^= )
Thanks for the work Tommy R!