MFactory LSD install DIY.

Subwoofer

Sergeant
Jan 9, 2020
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335i
Will be looking at making a DIY once this is done, but for now I need to know a few things.

I have a backlash tool and a bearing puller + separator.

My DIFF is the bolted one.

Is there anything else I need for the install ?

People online are saying bearings etc.

Will order x 2

33107505605 for the shaft seal.​


Im guessing this depends on what the condition is like ?

The shims should allow plug and play if I am correct ?
 
Last edited:

Subwoofer

Sergeant
Jan 9, 2020
267
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335i
I found this today haha
The amount of time I have spent trying to DIY. This guy just does it without even checking backlash.. Im in two minds about it. Because as long as you take the shims off bearings etc and put them back exactly how you got them off.
Technically there should be no problem. There doesnt seem to be reports of MFACTORY needing custom shims.
 

N54TT

Corporal
Jul 21, 2020
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2013 335is
The amount of time I have spent trying to DIY. This guy just does it without even checking backlash.. Im in two minds about it. Because as long as you take the shims off bearings etc and put them back exactly how you got them off.
Technically there should be no problem. There doesnt seem to be reports of MFACTORY needing custom shims.

Assuming the back lash needs to be set to factory specs, which I dont know the spec, Im sure once we put the shims and everything back to place and check the lash with a dial indicator then everything should be fine.
 

Cruizinmax

Corporal
Jul 18, 2018
121
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09 335i
When I installed my wavetrac I DID have to adjust my shims to achieve proper backlash and bearing preload. Attempting to install the original shims, they wouldn't even go in. The new shims needed to be quite a bit thinner. No way would I just throw a differential in without at least checking the backlash. Lots of stacked tolerances and we're dealing with tolerances of thousandths of an inch.
 
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N54TT

Corporal
Jul 21, 2020
136
41
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2013 335is
When I installed my wavetrac I DID have to adjust my shims to achieve proper backlash and bearing preload. Attempting to install the original shims, they wouldn't even go in. The new shims needed to be quite a bit thinner. No way would I just throw a differential in without at least checking the backlash. Lots of stacked tolerances and we're dealing with tolerances of thousandths of an inch.

Did Wavetrac supply the additional shims with the diff or this was something you had to purchase?
 

Cruizinmax

Corporal
Jul 18, 2018
121
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09 335i
Did Wavetrac supply the additional shims with the diff or this was something you had to purchase?
They are not included with the differential. They do sell them as does Mfactory if you need. In case you weren't aware, by shim it is actually just a different thickness snap ring which holds in the outer bearing race in the housing.
 

Subwoofer

Sergeant
Jan 9, 2020
267
48
0
Ride
335i
Assuming the back lash needs to be set to factory specs, which I dont know the spec, Im sure once we put the shims and everything back to place and check the lash with a dial indicator then everything should be fine.
I believe its set from factory as a pre set!
 

Subwoofer

Sergeant
Jan 9, 2020
267
48
0
Ride
335i
When I installed my wavetrac I DID have to adjust my shims to achieve proper backlash and bearing preload. Attempting to install the original shims, they wouldn't even go in. The new shims needed to be quite a bit thinner. No way would I just throw a differential in without at least checking the backlash. Lots of stacked tolerances and we're dealing with tolerances of thousandths of an inch.
Well that is interesting. So did you just throw the wavetrac shims ? Or was there grinding down etc?
 

Cruizinmax

Corporal
Jul 18, 2018
121
70
0
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09 335i
Well that is interesting. So did you just throw the wavetrac shims ? Or was there grinding down etc?
I had a local machine shop surface grind my c clip down to the proper thickness. If your ok with the wait then ordering the proper thickness c clip would probably be more cost effective. Also note that my situation needed a thinner clip. Yours may need a thicker one so grinding may not be an option in all cases. As well as obtaining proper backlash involves shifting the diff left or right in the case with a combination of shims so some may need a different shim on both sides.
 

Subwoofer

Sergeant
Jan 9, 2020
267
48
0
Ride
335i
I had a local machine shop surface grind my c clip down to the proper thickness. If your ok with the wait then ordering the proper thickness c clip would probably be more cost effective. Also note that my situation needed a thinner clip. Yours may need a thicker one so grinding may not be an option in all cases. As well as obtaining proper backlash involves shifting the diff left or right in the case with a combination of shims so some may need a different shim on both sides.
Please dont say that :( making the whole PnP seem like a myth.

What transmission and LSD did you install?
 

shushikiary

Sergeant
Jun 4, 2018
304
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335xi
Yea the carrier is not going to be the same dimensions to within a mil, so shimming will be required. I'm sad to hear the shims are the snap rings them selves. No wonder getting the snap rings in/out is such a huge pain because you have to then somehow make preload when installing the second snap ring, and overcome pre-load to remove them. This means either spreading the housing or compressing the bearings is the proper way to get the snap rings in/out. I wonder what the factory process is.

This also means you can easily have a machine ship mill the snap rings, as you may need thicker, or if they go too thin you're hosed. You'd need a set of different thickness snap rings just like you have a set of shims to do the job on say a dana 44 or dana 60.

This is why I love the ford 9 so much... want to change preload or lash? Just adjust the nut. Sure pinion depth is still shims, but you should only have to change pinion depth once or twice on a new gear setup if you measured it first.
 
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Subwoofer

Sergeant
Jan 9, 2020
267
48
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335i
Yea the carrier is not going to be the same dimensions to within a mil, so shimming will be required. I'm sad to hear the shims are the snap rings them selves. No wonder getting the snap rings in/out is such a huge pain because you have to then somehow make preload when installing the second snap ring, and overcome pre-load to remove them. This means either spreading the housing or compressing the bearings is the proper way to get the snap rings in/out. I wonder what the factory process is.

This also means you can easily have a machine ship mill the snap rings, as you may need thicker, or if they go too thin you're hosed. You'd need a set of different thickness snap rings just like you have a set of shims to do the job on say a dana 44 or dana 60.

This is why I love the ford 9 so much... want to change preload or lash? Just adjust the nut. Sure pinion depth is still shims, but you should only have to change pinion depth once or twice on a new gear setup if you measured it first.
My heart breaks. Reckon its worth buying the MFACTORY shims for a more PnP solution, or will that still need adjusting ? I dont believe I am up to the task of doing any shim work xD
 

shushikiary

Sergeant
Jun 4, 2018
304
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Well if the kit from MFACTORY has a bunch of different shims to place in front of a fixed size snap ring that would work, so you'd do your normal "carrier hokey pokey" during setup to get it right... ya know, put the carrier in with proper preload, measure lash, if it needs adjusting, pull carrier and adjust shims, measure lash, repeat until lash is right, pattern, if pattern needs to change pull carrier and adjust either side/side shims or pinion depth based on pattern, put carrier back in, measure lash - if it needs adjusting pull carrier, adjust shims, re-install carrier, measure lash... repeat until lash is good, re-pattern, and then adjust shims/pinion depth again if need be... bla bla bla until it's right. If you're installing new gears and you PROPERLY measure the depth of your pinion using the housing and use the marking on the pinion for it's mills of depth adjustment, usually you only need to adjust the pinion depth once maybe twice and you're set.

If you want some good write ups on the overall process there are a ton for the data 44/dana 60 out there. The difference here is how do you adjust the shimming and how are you supposed to get the snap rings in/out more easily than fighting pre-load each time? That I don't know on these diffs. I asked once how to do the shimming on these and got ZERO replies, so it seems most people are ignorant of how gear setups work on BMW's.

Normally when re-using gears you don't have to adjust the pinion depth at least, just pre-load and lash.
 

Subwoofer

Sergeant
Jan 9, 2020
267
48
0
Ride
335i
Well if the kit from MFACTORY has a bunch of different shims to place in front of a fixed size snap ring that would work, so you'd do your normal "carrier hokey pokey" during setup to get it right... ya know, put the carrier in with proper preload, measure lash, if it needs adjusting, pull carrier and adjust shims, measure lash, repeat until lash is right, pattern, if pattern needs to change pull carrier and adjust either side/side shims or pinion depth based on pattern, put carrier back in, measure lash - if it needs adjusting pull carrier, adjust shims, re-install carrier, measure lash... repeat until lash is good, re-pattern, and then adjust shims/pinion depth again if need be... bla bla bla until it's right. If you're installing new gears and you PROPERLY measure the depth of your pinion using the housing and use the marking on the pinion for it's mills of depth adjustment, usually you only need to adjust the pinion depth once maybe twice and you're set.

If you want some good write ups on the overall process there are a ton for the data 44/dana 60 out there. The difference here is how do you adjust the shimming and how are you supposed to get the snap rings in/out more easily than fighting pre-load each time? That I don't know on these diffs. I asked once how to do the shimming on these and got ZERO replies, so it seems most people are ignorant of how gear setups work on BMW's.

Normally when re-using gears you don't have to adjust the pinion depth at least, just pre-load and lash.
My heart breaks even more. Probably just going to take it to a shop. I feel like with engine building, transmission, and diff is not something I should play about with.

Thanks for all the info though, I dont feel like I have the necessary tools for this
 

Cruizinmax

Corporal
Jul 18, 2018
121
70
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Ride
09 335i
My heart breaks even more. Probably just going to take it to a shop. I feel like with engine building, transmission, and diff is not something I should play about with.

Thanks for all the info though, I dont feel like I have the necessary tools for this
The option I almost went with was syncrotech. They have an exchange program where they ship you an assembled diff with a mfactory lsd and you simply ship back your differential. It works out to be 1500.00 shipped after the core refund. Once you factor in the cost of the seals, shims, labor to install not a bad deal to know it's setup properly and has good bearings etc plus no downtime.
 
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Illsic_Design

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Feb 2, 2018
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The option I almost went with was syncrotech. They have an exchange program where they ship you an assembled diff with a mfactory lsd and you simply ship back your differential. It works out to be 1500.00 shipped after the core refund. Once you factor in the cost of the seals, shims, labor to install not a bad deal to know it's setup properly and has good bearings etc plus no downtime.
That really seems like the way to go if it comes with new bearings and seals. Can't really beat that price, might be what I do when I get an LSD soon.