[Lingling]

I just installed the a Quiafe LSD into my 2015 M235i 6MT today. The job was very easy to do, and I hope this guide helps anyone who decided to go the DIY route in the future. I wish I took pictures through the install, but I was so excited to install it I forgot to so I’ll do my best to explain everything in words.

Personel Needed: 1-2 people (having a friend assist you makes like much easier to adjust the differential in the proper angle)

Tools Needed: 8/10/13/18/21mm ratcheting or standard wrenches and sockets, 50mm wrench or 50mm crows foot(I used this),T60 Torx ,T45 Torx,14mm Allen, large flat head screw driver, dead blow hammer or mallet, block of wood, set of picks, 3/8 and 1/2 torque wrench, jack and jack stands.

Optional Tools: BMW Axle tool (not needed at all. I had it in my tools today and didn’t even end up using it bc of how much of a hassle it was), power tools, orange loctide, Transjack.

Install Time: 2-3 hours based on skill level. I have the whole diff removed in about 1 1/2 hour and about an hour to install. My mechanical background is 4yrs of backyard DIY and a General Service tech at pepboys. So if that tells you anything im no professional.

Difficulty Rating: 2.5/5 (very simple once you know what you are doing)

Items needed: 1x BMW LSD( m performance, Quiafe, Wavetrac whatever you would like), CV Axle grease, 2 quarts of differential fluid(I used Redline 75W90 NS) if running the m performance get the LSD fluid from BMW.

Optional items: 1x BMW driveshaft Nut (PN:BMW-33127607158) *optional but highly recommended. 2x BMW axle lock ring (BMW-33131214961)

Instructions Removal:

Step 1: Either have the vehicle on a lift(recommended) or jack the rear up as much as you can you’ll want as much room as you can get in the rear.

*for manual cars leave your car in gear with the ebrake up, and you automatic drivers leave it in park.

Step 2: Remove exhaust/ Rear Brace

You can either completely remove the exhaust or lower it by removing the 2x 13mm nuts holding the muffler in. I just lowered it instead of fully taking it apart. The rear brace is held in by 2x T-60 bolts on the outter most and 6x T-45 bolts in the inner, remove this fully from the vehicle.

Step 3: Remove rear vibration absorber.

This is located right in front of the battery box The space is very limited so you won’t be able to get a E10 socket in there. I used a 8mm ratcheting wrench to remove it off the vehicle.

Step 4: Remove rear differential bolt and nut.

After removing the rear vibration absorber this will expose a bolt. This will require a 21mm socket and a 21 mm wrench. The socket will go on the nut that is located on the top left of the rear differential. It is a little of a blind spot so feel around.

*note this bolt does not fully remove due to the battery box being in the way, once the nut is released from the bolt slide bolt all the way so it’s against the outer battery box.

Step 5: remove 50mm drive shaft nut.

First support differential with a jack then using either a 50mm crows foot(what I used) or a 50mm wrench. this bolt is extremely tight and where you will be using most of energy.

If you are facing the front of the car with your back to the rear of the car turn the wrench counter clockwise towards the passenger side of the vehicle.

*do not use the preload nut as support this will cause irreversible damage. The nut is a 12point you can’t miss it, just avoid touching it and you will be fine.

Step 6: Seperate drive shaft from differential

I did this by slightly loosening the front 2 18mm bolts and pushing the differential towards the rear of the car.

* note the drive shaft will fall downwards once disconnected from the differential just tie it up with a bungee cord

Step 7: Removing Axles

Remove the 2x 18mm bolts holding in the differential. Then you can either use the bmw axle tool or use a large flat head screw driver and wedge it inbetween the axle and differential. I had access to both and just used the screw driver found it much easier and quicker to pop the axles out.

*I found it easier to remove the passenger side axle first then tilt the differential and remove the driver side axle.

Congrats you have removed the oem differential!!

Instruction Instalation:

Basically we are going to do everything in reverse.

Step 1: installing axles back in

Remove old axle lock rings with 2 pick tools and snap the new ones on. I installed the driver side axle first by tilting the axle slighting and inserting the axle. Then using a plank of wood as a buffer between the axle and your mighty hammer. Strike the wood until your axles are in fully then repeat on the other side.

Step 2: reattach drive shaft to differential

Before doing so you will want to clean out the teeth of the drive shaft and differential input shaft and apply a good amount of cv axle grease.

If you are reusing the drive shaft nut apply loctide(orange) or for new bolts the loctide is preapplied already.

Attach the drive shaft to differential and tighten the nut until it won’t tighten any further. I did about 100nm plus 90 degrees.

* remember you only have 5 minutes to install the nut before the loctide starts to cement itself

Step 3: install 2x18mm bolts and 1x 21mm bolt/nut

Using the jack to get the bolts lined up insert the 18mm bolts and torque to 100NM Then install the 21mm bolt/nut and torque to 165NM

Step 4: Install rear vibration absorber

using the 8mm wrench I tightened to hand tight and then gave it about 90degrees.

Step 5: Install rear brace

The T60 are torqued to 100nm plus 90 degrees and the inner T45 are torqued to 24nm plus 90degrees.

Step 6: install exhaust hangers

Step 7: add diff fluid

Remove the 14mm Allen(might be a different size I forgot) and using a fluid pump add fluid. Mine took about 1.4 quarts of the Redline 75W90 NS

That’s it for installation remember the new drive shaft nut needs to set for a minimum of 2 hours or 24 hours if you are using your own loctide. After that take it for a spin

*For Quiafe differentials once the drive shaft nut is set you can full send as the quaife differential has no break in period.

*For M performance differentials (or any other clutch type differentials) do 8 full wheel lock at low speeds at each side and then 500miles of normal driving then you can send it!!

I apologize if this isn’t the most detailed guide, when I was looking up information regarding this it was very limited and I wanted to do my best and help y’all out. You don’t need speciality tools and the task really isn’t that hard either!!

If you guys have any question let me know!!

Birdsauto made it a very simple process of getting my differential assembled in the UK and shipped to the USA.

[Pr0ximity]

Fantastic write-up, thank you for sharing

[cooolone2]

Thank you for posting!

[BAT240]

First off, great write up. Thanks.

I am looking to do the same on my 2018 m240i 6MT RWD. Do you (or anyone else) know if there are any differences for the m240 vs m235? Are the part #s the same for the driveshaft nut and lock rings?

[Lingling]

Originally Posted by BAT240

First off, great write up. Thanks.

I am looking to do the same on my 2018 m240i 6MT RWD. Do you (or anyone else) know if there are any differences for the m240 vs m235? Are the part #s the same for the driveshaft nut and lock rings?

The driveshaft nut and lock rings are the same part.

The differentials themselves drive ratios are different I think. I ended up changing from a 3.08(f22) to a 3.23(f30) which allowed for faster acceleration but lower top end speed. If you have a manual transmission like I do there are no error codes that pop up for changing a different drive ratio, but for automatics I believe your car will freak out. If you have any more questions or need help getting one lmk I’d be more than happy to help.

[BAT240]

I just ordered the M performance LSD and the other parts. Everything should be here in about a week. I’ll let you know if I have any questions. I have a lift so hoping the install will go smoothly. Can’t wait to experience the difference. Thanks again

[Lingling]

Originally Posted by BAT240

I just ordered the M performance LSD and the other parts. Everything should be here in about a week. I’ll let you know if I have any questions. I have a lift so hoping the install will go smoothly. Can’t wait to experience the difference. Thanks again

Heck yeah man you’ll really enjoy how the car drives once the LSD is installed. Remember the m performance lsd is a clutch type so it’ll require a break in. 8 turns on the left and 8 turns on the right followed by a 300-500mi normal driving before carving those corners. I’m located in PA/NJ so if you do end up needing a hand I can see if I can help you. I also wrote up a guide that you can follow it’s pretty detailed and goes step by step on how I removed and installed.

[SpencerC_6MT]

Originally Posted by Lingling

If you have a manual transmission like I do there are no error codes that pop up for changing a different drive ratio, but for automatics I believe your car will freak out.

Put a 3.46 Wavetrac in my M240i 6MT. Factory for the 6-speed 240 is a 3.08, which is apparently a big enough gap that the ECU thinks the clutch is slipping every time you start the car. If you don't feel like paying for a custom tune - the only way to fully remedy it - I've found the limp mode goes away by simply accelerating up to about 15mph and letting it coast in-gear without touching the clutch pedal for a few seconds. The "drivetrain malfunction" warning triangle won't go away, but you get full engine power until the next time you turn off the ignition.

Sidenote: automatic 240's actually got a 2.81, unlike the M235iA which shares its 3.08 with the manual.

[Lingling]

Originally Posted by SpencerC_6MT

Put a 3.46 Wavetrac in my M240i 6MT. Factory for the 6-speed 240 is a 3.08, which is apparently a big enough gap that the ECU thinks the clutch is slipping every time you start the car. If you don't feel like paying for a custom tune - the only way to fully remedy it - I've found the limp mode goes away by simply accelerating up to about 15mph and letting it coast in-gear without touching the clutch pedal for a few seconds. The "drivetrain malfunction" warning triangle won't go away, but you get full engine power until the next time you turn off the ignition.

Sidenote: automatic 240's actually got a 2.81, unlike the M235iA which shares its 3.08 with the manual.

Wow didn’t think our cars would go into limp mode like this. Maybe consider a boost reduction in the lower gears VIA BM3. My Quaife is a 3.23 I haven’t had any issues in terms of launching it and driving hard. It’s a 6MT as well