How To: Mfactory LSD Diff + Diff Bushings install.

[grmnmx5_]

This is a guide on how to replace a non-m Z4 (same as a non-m e46, and very close to first-gen e90) diff and diff bushings.

As I was looking down at the time of finally needing to replace the diff bushings I figured while I'm down there it would be a great time to swap out the old worn open diff. I was lucky enough to be able to follow Gary T's diff install/removal guide but figured for those who are doing the full job it may be easier to have everything on hand in one go.

DISCLAIMER: I am not a professional this is simply a guide to help you out as it would've benefitted me if I had a guide. please do so at your own risk!

Tools Needed:
Mfactory LSD
Magnetic bowl to hold diff bolts
wobble extensions
75w90 diff oil
the right stuff gasket maker
flat heads
chisel
pry bar
torch(optional)
e12 torx socket
14mm allen key socket
8mm socket
13mm socket
16mm socket
18mm socket
21mm socket
x2 clamping style bearing separators (for diff bearings)
FWD Bearing remover kit
5/12'' home depot bolt with grade 8 washers
Big 90-degree needle nose pliers (removal of diff c clips)
lastly some patience.


First thing is to get the car as high as possible to be able to have enough clearance to get under and get all the stuff out. wheels were also taken off to make more room.

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Next up remove the aero ducting and reinforcement plate. Aero Duct is x10 8mm nuts
reinforcement plate is x2 13mm's x4 16mm's and 2 8mm bolts for the exhaust hanger.

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once the aero duct and reinforcement plate are off move to the heatshield and unbolt it. you will need this unbolted to give you a little more room to access the pushrod bracket, or you can choose you to bend the heat shield (it bends back into place) once it's unbolted push the heatshield to the front of the car.
after that it should uncover the pushrod bracket, x2 18mm bolts. once again you will have the heatshield possibly blocking it so bend/ move as necessary. (wasn't able to nab a photo but the photo listed below as item #11)

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Next move over to the Pull rods (Listed as Item 16) x2 18mm's per rod and x13mm nut

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once the pull rods are off go to the back of the car and remove x4 13mm nuts from the exhaust hangers, x2 on each hanger.
some say to let it dangle which is fine but i chose to support mine up the jack. Next, remove the sway bar, i chose to fully remove it since i was trying to make as much space as possible. x13mm on the bracket, then use a flat head to release it from the tab. then x2 13mm's up top on the control arm.

I chose to work front to back as best as possible to maintain organization throughout the bolts.

next up is finally to remove the driveline. have a friend handy for this one. x4 e12's come off the driveshaft, use the e12 on a wobble extension to get as much room as possible. make sure the e12 is FULLY SEATED onto the bolt head. you can easily strip these bolts. have your buddy put the car in gear and the parking brake up for you as you loosen the bolts up. rotate the driveshaft by hand to get the right angle on them. it is very tight down there.

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lastly, the same thing applies to getting the axles off. have your buddy up in the car as you're down there. this is a bit tedious as the cv axle boots make it a little tough to angle the socket and extension properly, but this is why you get the wobble extensions to help with this. these will take some time. the passenger side comes off easy as you have some good space, the driver side not so much. take your time you do not want to snap any of these.

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once this is done get ready your diff is about to come out of its hiding hole.
get your jack and put some wood on the base of it to support it. remove the x2 from 18mm bolts and then move to the rear 21mm bolt. you may need to angle off the driveshaft to get enough room. you will use a 21mm open wrench on the backside. once all bolts are out the diff needs to be angled away from the subframe. push the front of the diff forward to get the rear of the diff out, then the diff will want to come straight down on you, you will need some arm strength to angle it out the rest of the way, be careful she's heavy.

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Congrats, the diff is out! I didn't choose to drain the diff while it was in the car. I unbolted the rear cover and let it all out in a plastic tub.
now comes the fun part of getting your LSD in!

Remove the diff cover and drain the diff oil, x8 16mm bolts. let it drain for a bit into a tub.
next up is Grab a pry bar or a very durable flat head screwdriver, and use a hammer/ rubber mallet to smack out the axle stubs. will take some time and force but they'll come out. grab your pry bar again and remove the axle shaft seals (you should be replacing these anyways), get it under the seal, and pry up to get them out of their hole. repeat for both sides. use the old seals to set in the new ones. these do not sit all the way in, maybe 4-5 mm in or so.

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now your c clips are exposed, grab those 90-degree pliers and use 2 hands to get them squeezed and out. please put these with their corresponding axle stub/ side, do not mix these up. once both sides are off you should be able to wiggle the diff left to right to push the outer bearing races out. once those are out angle the passenger side of the diff no ring gear) in towards the front of the housing, then grab the ring gear side and pull towards you, it will angle out fairly easily.

now to pull your ring gear off I suggest throwing the diff into a vice. it will help give you some needed leverage to get the bolts out, these should be 18mm. you may want to tap the side of the ring gear with a rubber mallet to loosen it and then use a hand to catch it.

now here comes the fun part of getting the bearings off. DO NOT i repeat DO NOT mess these up they are incredibly hard to find and the corresponding part numbers from parts stores are now it, stay away from lm503349a! it does not fit!

use x2 bearing separator tools to pull the bearings off, for the driver(ring gear side) its simple; adjust the separator to touch underneath the race, and clamp it down from the sides. now thread the puller bolts (this is why you need 2) in, and double nut the threads in order to create a lock on it and be able to bolt it down. use wood to protect the metal on the diff but only if you care about it. do full turns from side to side and it will slowly release the bearing, take your time please! do not mess these bearings up and make sure the separator contacts the bottom of the race.
now for the passenger side it's a bit more of a process, the separator does not fit under the race so you have to use a flat head/ chisel to be able to work the bearing off (at least until you can put the separator under the race). work it off a bit, this will take some time, but once you have enough of a gap to put the separator in, you're golden!

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awesome now it's time to swap your LSD on.
throw the lsd in the freezer to shrink the metal a bit (anything helps). make sure to mark the bearings based on what side they came out of, put the bearings in the oven to expand, an hour or 2 at 275 should do it. once some time has passed pull the diff out and then bring the bearings, seat it as best and as quickly as you can then use wood accompanied by a rubber mallet to seat the bearing on, and boom, your LSD is ready to swap back in!

Alright now go ahead and reverse all the steps and you are golden and will have a fresh rear end!

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this last section is dedicated to the swap of the diff bushings, my swap used a combination of a fwd bearing removal kit and home depot. use a 5 1/2 to 6' hardened bolt, galvanized or standard grade 5 may cut it, but the washers must be grade 8! they will bend. my diff bushings were clunking around and not to mention were frozen inside the subframe. use the combination of bolts washers and bearing receiving cups to push the bushings out, you can opt to torch the fronts as well and they will come out fairly easily. the rear diff bushing is a huge pain. it will take some time and patience and I do not recommend using an impact for this. it can shred your home depot bolt.

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here are some good video links for more visual info that helped me.
https://www.youtube.com/watch?v=g-giRKAkzOs&t=314s
https://www.youtube.com/watch?v=2H62VVLj0LM&t=39s
https://www.youtube.com/watch?v=yBAvCM3MuL0
https://www.youtube.com/watch?v=T43vjZeBtOA
https://www.youtube.com/watch?v=TZWIm2PDpYU&t=164s

any other suggestions please let me know!

[r3vmatch]

Hey grmnmx5_,

Great write up! To confirm, did you get the M-Factory MF-TRS-05E46A LSD? Confirming your differential is the 188L.

Also, did you consider using this bearing kit? : https://www.turnermotorsport.com/p-3810 ... -kit-plus/ I guess INA makes a bearing kit ( 462014810 ) which I see on eBay, but from EU sellers.