[Polo08816]

This is write-up is not meant to be a complete standalone DIY. This is just bits and pieces of advice/suggestions I have for the DIYer when following the ISTAD procedures pdf I posted in Post #145. I recommend doing this procedure with the help of another person. My girlfriend is awesome because she wakes up at 5am on Sundays to help me out on these installs.


I finally received all the tools after 2-3 weeks since the special Torx socket needed to be shipped from Germany. All special tools and parts came from getBMWparts. They were extremely helpful in translating BMW tool numbers to part numbers.


Pry-bar of Thor. BMW Tool # 33 5 120. BMW Part Number 83300495851. This is required for the removal and install of the rear differential. I haven’t come up with an alternative way around (as laid out in previous posts) so I dropped some coin on it. BMW went away from the bolted output shaft design so this special tool is now required.




Here’s how the BMW M Performance Limited Slip Differential came:



It comes with a new insert nut so you don’t need to order the repair kit when ordering this differential.


First off, remove the exhaust system and remove the heat shields as performed in Post #145.


Next, disconnect the propeller shaft. I supported the propeller shaft with two jack stands. I then slackened (not fully removed) the two bolts holding the center universal joint (bearing). I secured the propeller shaft against rotation by inserting a screw driver through the u-joint. Usually this is not recommended, however, the BMW ISTAD Rheingold specifies this as an acceptable way to brace the propeller shaft. My guess is that there’s sufficient resistance already since the propeller shaft remains bolted to the transmission.




Then, open the insert nut which connects the propeller shaft to the rear differential. I used a HP Autowerks differential tool for this step. The insert nut must be opened in a CLOCKWISE direction. The insert nut is opposite of normal tightening/loosening directions.




Propeller shaft disconnected from the rear differential.




Remove the rear vibration damper. Removal on my car required a special Torx E10 socket (BMW tool # 2 240 515 and part number # 83302240515)


Now support the differential using a transmission/differential jack. The jack I used wasn’t the best. The chain used to secure it didn’t secure it that well, so I would recommend 1-2 ratcheting straps for someone doing this in the future. The reason is because you will need to tilt the differential to remove and install the output shafts.



Make sure you strap it down between the final differential (back) cover and axle shafts.




Now remove the left (passenger side) output shaft based on the ISTAD Rheingold procedure. You won’t be able to remove the right (driver’s side) output shaft just quite yet. The rear differential mount blocks you from getting a good point of leverage using the special pry bar from the right side.






Use jerky movements and the output shaft will eventually pop out.




Now that you have pressed out the left output shaft, you can release the two front differential bolts using an 18mm socket and breaker bar. This is a long bolt so once you have it loosened, you can go ahead and use an air ratchet to remove it. Make sure you’ve properly supported the differential with that transmission jack.




Remove the rear bolt. There is a nut on the back of the bolt which needs to be replaced. You’ll need to use a breaker bar to secure the nut against rotating with the bolt when you are trying to remove it. I believe they both were 21mm.




Now lower the rear differential.




Pry out the right (driver’s side) output shaft. This one gave me heartache because I could not find a good place on the actual differential to use as a leverage point for the special pry bar. I ended up needed to reinsert the front and back differential bolts and then pressing against the transmission jack to pop out the right output shaft.




Stock open rear differential finally lowered.




Place the new BMW M Performance Limited Slip Differential on the transmission jack and secure it using chain/ratcheting straps.






Unfortunately, I missed a lot of photos at when trying to get the output shafts into the new differential. This was the toughest part of the job in my opinion. The steps I took were different than what is written in ISTAD Rheingold. The steps I took were roughly in this order:

1. Raise differential on transmission jack.
2. Feed right (driver’s side) output shaft into differential.
3. Brace differential against rear subframe. This was done because tapping the special pry bar accessory – the BMW cinching device – with a rubber mallet wasn’t seating the output shaft back into the differential. In retrospect, I could have done a better job of aligning the splines of the output shaft to the grooves in the differential by simply rotating the output shaft until it fit better.
4. Tap right output shaft into differential with rubber mallet. Don’t use a metal hammer. If the splines and teeth are not lined up correctly, tapping the cinching device with a metal hammer may damage the output shaft and rear differential.
5. Lower the differential and turn it so that the left output shaft can be fed into the differential.
6. Feed left output shaft into differential.
7. Raise differential back up into the subframe to a position where you can re-insert the front and rear differential bolts/nuts. Screw in a few threads in so that the differential won’t move. It is now braced.
8. Tap the left output shaft into the differential using a rubber mallet.

Now insert the front and rear differential bolts/nuts but do not torque down yet.
Release the chain/ratcheting strap.




Lower your transmission jack. Differential should be in position.




Now it’s time to connect the propeller shaft back to the differential. Once you start to screw the insert nut in, you have approximately 5 mins to complete this procedure. I don’t have many pictures for this portion of the install but here are the rough steps I took:

1. Slide propeller shaft to the limit position onto insert nut.
2. Fasten the insert nut to propeller shaft by going in a COUNTER-CLOCKWISE direction.
3. Insert center universal joint bolts and screw on a few threads.
4. Torque down insert nut using HP Autowerks differential tool at 85 Nm.
5. Torque down center universal joint bolts to 19 Nm.

Picture of final install:



Reinstall heat shields and complete exhaust system.



Total time for my install:
6 hours
I don’t think I could ever get it down to the 2 hours spec’d for dealers in BMW KSD. I think if I were to do it again, I could do it around 3 hours.


Initial review of the differential:
It's awesome compared to the stock open differential. When you're accelerating hard out of a turn, you can hear the clutches working and no DSC/traction control intervention to be found. I can't wait to experiment with this at some HPDEs this upcoming season.

[enjoythemusic]

Congrats Polo and great write-up! Really appreciate your efforts in posting pics and giving us details. Due to adding power to the new-to-me 435i and planning occasional road course track events, am having the M LSD installed shortly.

IMHO the LSD should have been standard, or at least part of something like the MPPK package or....

Thanks again Polo, looks like a solid upgrade for drivers.

[mattpete13]

wish I had the cash for this upgrade, although the desire to eventually get into an M3 keeps me from saving up for it.

awesome write up!!

[Polo08816]

Originally Posted by enjoythemusic

Congrats Polo and great write-up! Really appreciate your efforts in posting pics and giving us details. Due to adding power to the new-to-me 435i and planning occasional road course track events, am having the M LSD installed shortly.

IMHO the LSD should have been standard, or at least part of something like the MPPK package or....

Thanks again Polo, looks like a solid upgrade for drivers.

Originally Posted by mattpete13

wish I had the cash for this upgrade, although the desire to eventually get into an M3 keeps me from saving up for it.

awesome write up!!

I drained the differential fluid today and replaced it with Castrol Syntrax 75w-140 which is an approved BMW gear oil for a LSD (see PDF posted in #145).

I used a multi-use fluid transfer pump found at Harbor Freight and it worked perfectly.

1. Remove the drain/fill bolt using a 14mm Allen socket. It does not require a lot of force.
   
2. Insert tube to draw off LSD fluid. It will look pretty gross.
   
3. Insert input tube of pump in a .5L bottle of Castrol Syntrax 75w-140. Insert output tube into the differential fill/drain hole.
   
4. Pump gear lube into differential until lube drips out of the fill/drain hole. Filling quantity will be approximately ~0.8L.
   
5. Re-install fill/drain plug with your 14mm Allen socket. Torque it to approximately 60 Nm.

[Polo08816]

If anyone is interested, I'm selling the tools I used for this DIY here:

http://f30.bimmerpost.com/forums/sho...1#post21487001

Originally Posted by Polo08816

I've just completed my BMW M Performance Limited Slip Differential install on my 2014 F30 335i RWD SAT M Sport. I wrote a DIY write-up here on how to use these tools.

Here are the tools that are included in this sale:

1. BMW tool #: 2 240 515
BMW part #: 83302240515
Torx E10 socket required to clear the fuel tank in order to remove vibration damper.

2. HPA Differential tool
Allows you to disconnect and rejoin driveshaft (aka propeller shaft) from differential.

3. BMW tool #: 33 5 120
BMW part #: 83300495851
BMW special pry bar used to remove and install output shafts into differential. Here's the ISTA page on this tool.
This is a toolset that includes the following BMW tools:
33 5 121
33 5 122
33 5 123
33 5 124
33 5 125
33 5 126
33 5 127

4. BavAuto CV Axle Prybar.
This was not needed for my RWD car.
https://www.bavauto.com/b8800037


These are all the special tools required to:

• Remove vibration damper on the back of the differential
• Disconnect driveshaft
• Separate output shafts from differential
• Re-insert output shafts into differential
• Re-join drivewhaft to differential

[F32Fleet]

Originally Posted by Polo08816

I drained the differential fluid today and replaced it with Castrol Syntrax 75w-140 which is an approved BMW gear oil for a LSD (see PDF posted in #145).

I used a multi-use fluid transfer pump found at Harbor Freight and it worked perfectly.

1. Remove the drain/fill bolt using a 14mm Allen socket. It does not require a lot of force.
   
2. Insert tube to draw off LSD fluid. It will look pretty gross.
   
3. Insert input tube of pump in a .5L bottle of Castrol Syntrax 75w-140. Insert output tube into the differential fill/drain hole.
   
4. Pump gear lube into differential until lube drips out of the fill/drain hole. Filling quantity will be approximately ~0.8L.
   
5. Re-install fill/drain plug with your 14mm Allen socket. Torque it to approximately 60 Nm.

how's the LSD working out?

[ronanz]

Originally Posted by Polo08816

This is write-up is not meant to be a complete standalone DIY. This is just bits and pieces of advice/suggestions I have for the DIYer when following the ISTAD procedures pdf I posted in Post #145. I recommend doing this procedure with the help of another person. My girlfriend is awesome because she wakes up at 5am on Sundays to help me out on these installs.


I finally received all the tools after 2-3 weeks since the special Torx socket needed to be shipped from Germany. All special tools and parts came from getBMWparts. They were extremely helpful in translating BMW tool numbers to part numbers.


Pry-bar of Thor. BMW Tool # 33 5 120. BMW Part Number 83300495851. This is required for the removal and install of the rear differential. I haven’t come up with an alternative way around (as laid out in previous posts) so I dropped some coin on it. BMW went away from the bolted output shaft design so this special tool is now required.

.....

You're a stud!! .

.

[joon]

Amazing write-up... thanks a lot for sharing this

I have one quick question... in all the manuals I see the instruction that the insert nut on the differential to driveshaft connection will "harden", and that you need to complete the procedure in 5 minutes or so... is there some kind of glue or locktite on the nut?

[Polo08816]

Originally Posted by F32Fleet

how's the LSD working out?

It's working out real well. I like it so far and the engagement has become smoother and less noisy after the first 1,500 miles.

It's a great feeling when you can be more aggressive on the throttle coming out of a turn, especially in less than inclement conditions. The rear drive wheels just hook up.

There is minor DSC intervention, but my guess is that's when the DSC system detects a difference of average wheel speed between the front and rear axles - and not side to side

With an open diff, you could feel the rear sway left and right when the DSC system was pulsating the brakes.

Originally Posted by joon

Amazing write-up... thanks a lot for sharing this

I have one quick question... in all the manuals I see the instruction that the insert nut on the differential to driveshaft connection will "harden", and that you need to complete the procedure in 5 minutes or so... is there some kind of glue or locktite on the nut?

There is some debate on whether that hardening time is necessary. I followed it just for peace of mind.

There is no glue or loctite on the nut, but the instructions do call for the application of a grease to the insert nut parts.

83230417754
GREASE

[XutvJet]

Thanks for the detailed write-up. A few questions:

1) Isn't the half-shaft simply held into the diff with typical retention cir-clip? Do you think the BMW pry bar is necessary? The reason I ask is many FWD cars use this arrangement and simply tugging on the half-shaft and universal housing will release the cir-clip. Perhaps there's not enough room to do that or maybe a lot of force is needed to unseat the cir-clip?

2) With respect to getting the half-shafts back into the diff, can you not simply push them in with a quick forward jolt to seat the cir-clip? Again, this comes from my FWD car days.

3) Did you need to loosen and/or remove anything from the suspension like control arms, sway bar links, etc?

[Polo08816]

Originally Posted by XutvJet

Thanks for the detailed write-up. A few questions:

1) Isn't the half-shaft simply held into the diff with typical retention cir-clip? Do you think the BMW pry bar is necessary? The reason I ask is many FWD cars use this arrangement and simply tugging on the half-shaft and universal housing will release the cir-clip. Perhaps there's not enough room to do that or maybe a lot of force is needed to unseat the cir-clip?

2) With respect to getting the half-shafts back into the diff, can you not simply push them in with a quick forward jolt to seat the cir-clip? Again, this comes from my FWD car days.

3) Did you need to loosen and/or remove anything from the suspension like control arms, sway bar links, etc?

1. I think the issue is that there's not a good way to insert a standard pry bar to gain the leverage needed to pop the half shaft out without damaging some parts to include the plastic guard. I attempted this with a $30 CV axle pry bar I bought - a picture of it was posted earlier in this thread when I was trying to figure out a workaround for this BMW pry bar.

2. You may be able to. However, I wanted to make sure I would be able to complete the project in 1 day since I was renting the lift bay per hour.

3. No.

[f30_garcia]

This is fantastic

[dr.roro]

How much should I expect the dealership to charge for this install?

[Polo08816]

Originally Posted by dr.roro

How much should I expect the dealership to charge for this install?

Post #145 has a PDF which includes BMW labor estimates for the procedure towards the end of the PDF.

[dr.roro]

Originally Posted by Polo08816

Post #145 has a PDF which includes BMW labor estimates for the procedure towards the end of the PDF.

Downloaded the PDF and I'm not seeing anything indicating labor estimates.

[Polo08816]

Originally Posted by dr.roro

Downloaded the PDF and I'm not seeing anything indicating labor estimates.

Page 76.

Divide FRUs by 10 and that's how many hours of labor.

[Red_Baron]

I ordered an M Performance differential for my 340i 8AT. The local dealers asked for ridiculous prices ($2500 & $3500 without labor).

It seems like no additional parts are needed for installation. (such as differential oil, gaskets, nuts, bolts, etc.) The local independent shop doing the installation may not have the parts on hand and I would like to order them ahead of time.

Can anyone confirm this?

[zinner]

There are some clips that aren't strictly needed but a good idea and I think they are like a few bucks. The fluid can be 100 bux if you use the BMW fluid. Mine came filled with fluid from the parts department as part of the price.

[JaredG_F30]

Originally Posted by Polo08816

Page 76.

Divide FRUs by 10 and that's how many hours of labor.

So 2.5 hours to replace the rear diff? That's how I read it. At $180/hour that comes out to $450 in labor. Seems like a wash if the special tools are $450.

BTW this will be my next upgrade! Running a stock tune on the street with an open diff is all good but once you bump the power with a tune it's apparent an LSD is needed!

[Polo08816]

Originally Posted by JaredG_F30

So 2.5 hours to replace the rear diff? That's how I read it. At $180/hour that comes out to $450 in labor. Seems like a wash if the special tools are $450.

BTW this will be my next upgrade! Running a stock tune on the street with an open diff is all good but once you bump the power with a tune it's apparent an LSD is needed!

Pretty much. I bought the tools and did it for personal enjoyment.

[JaredG_F30]

Originally Posted by Polo08816

Pretty much. I bought the tools and did it for personal enjoyment.

Gotcha!! I would love to do it myself but don't have access to a lift and I'm pretty sure doing this on my back with the car on jack stands would not be that enjoyable

[ChrisFulton]

Originally Posted by Polo08816

I drained the differential fluid today and replaced it with Castrol Syntrax 75w-140 which is an approved BMW gear oil for a LSD (see PDF posted in #145).

I used a multi-use fluid transfer pump found at Harbor Freight and it worked perfectly.

1. Remove the drain/fill bolt using a 14mm Allen socket. It does not require a lot of force.
   
2. Insert tube to draw off LSD fluid. It will look pretty gross.
   
3. Insert input tube of pump in a .5L bottle of Castrol Syntrax 75w-140. Insert output tube into the differential fill/drain hole.
   
4. Pump gear lube into differential until lube drips out of the fill/drain hole. Filling quantity will be approximately ~0.8L.
   
5. Re-install fill/drain plug with your 14mm Allen socket. Torque it to approximately 60 Nm.

At what mileage did you change the fluid?
I just had the LSD installed yesterday and the technician said to bring it back after 1200 miles for the fluid change.
Also curious as he said that the diff is initially filled with brake fluid?