kylerwinters

Lurker
May 25, 2019
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So I found a 2011 e92 335i manual front diff with 54k for $200 bucks so I bought it. When I opened the diff, sadly I found that it was welded.
This is for part number 31517533433.

So it does look like they eventually welded it. Now we just need to find the start date range of the welded diffs
 
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shushikiary

Sergeant
Jun 4, 2018
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Thanks for the info, but that does suck.

It seems all the data for the manuals has been 2009 or earlier so far until yours, so it seems the cross over happened sometime in 2009.

Interestingly realoem does not list anything for part number 31517533433. I'll have to call the dealership to get details on that part number.

Dealership says the part number is also no good. Do you have the vin number for the car it came from? I'd test the gear ratio , it may very well not be for a manual.
 
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The Banshee

Corporal
Nov 18, 2017
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Lehigh Valley PA
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2008 335xi coupe 6466 MT
Any ideas on this? I just spoke to M-Factory about a set of coil-overs and mentioned the front LSD. They are still willing to build it. Just waiting on us!
 

spiritsavage

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Sep 12, 2019
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I really want to, but it'll be about a year before I get there...

Edit: Maybe a few months o_O
 
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scrllock

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Dec 17, 2018
267
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2011 335xi
My only question is... How did it go from 10-30 in two years?: https://www.e90post.com/forums/showthread.php?t=1319061

 
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spiritsavage

New Member
Sep 12, 2019
4
0
0
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2011 e90 335Xi N55
The one page I skip... Sorry about that. That makes sense. I mean, I could say that I'll absolutely do it when I save up for it, but I'm just now starting to save up for it. I'll do this before any other mods just to know I have it.
 

The Banshee

Corporal
Nov 18, 2017
175
104
0
Lehigh Valley PA
Ride
2008 335xi coupe 6466 MT
I'm about to just send them mine and say build it, I need it for tx2k.

Did you ever follow through with this? How much to build say 10 of them?

Can anyone summarize the most recent findings on how many types of differentials there are? and what the differences between them are? I am guessing we have to present this info to MFactory so they know what to build.
 

shushikiary

Sergeant
Jun 4, 2018
304
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335xi
So far I still believe that all manuals are a bolted front diff. The one case someone said they had a non bolted manual front diff the part numbers were very wonky. From what I could tell it was a totally different gear ratio and not from a E9X manual.

This means that there already exists a quaife torsen LSD that works and you can just swap the carrier over with no issues for the front diff. On the rear diff, the majority of them are welded for most E9X Xi's, and thus you have to have the gear cut of and machined or you have to buy new gears with the LSD. I posted a chart that isn't perfect but gives a good idea of what the breaks look like for welded vs not welded rear diffs.

Bird, in Europe, is happy to do the cut off and machine of welded diffs, they still do it for the rear's. So if they had to the auto guys could go that route.

It would be cheaper though to get enough people that need gears to get them to make the gears for the auto guys. As stated, the manual guys don't need gears, but I wouldn't complain if I had to buy a new set of gears for the front of my manual. Not sure having 2 different ratio's would require more people or not.
 
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Twisted Tuning

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Oct 25, 2016
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www.twistedtuning.com
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N54 and N55 Cars
So far I still believe that all manuals are a bolted front diff. The one case someone said they had a non bolted manual front diff the part numbers were very wonky. From what I could tell it was a totally different gear ratio and not from a E9X manual.

This means that there already exists a quaife torsen LSD that works and you can just swap the carrier over with no issues for the front diff. On the read diff, the majority of them are welded for most E9XXi's, and thus you have to have the gear cut of and machined or you have to buy new gears with the LSD. I posted a char that isn't perfect but gives a good idea of what the breaks look like for welded vs no welded rear diffs.

Bird, in Europe, is happy to do the cut off and machine of welded diffs, they still do it for the rear's. So if they had to the auto guys could go that route.

It would be cheaper though to get enough people that need gears to get them to make the gears for the auto guys. As stated, the manual guys don't need gears, but I wouldn't complain if I had to buy a new set of gears for the front of my manual. Not sure having 2 different ratio's would require more people or not.


does any have a bolted front diff they can send in?
 

Maniac0908

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Mar 22, 2018
109
6
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07 335xi
Have we considered getting propulsive dynamics/Precision Raceworks involved? Since they made the upgrades for the auto trans maybe they can help getting this going? And even getting some upgrades internal for the transfer case!?
 

scrllock

Sergeant
Dec 17, 2018
267
152
0
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2011 335xi
They packaged up some clutches and did testing/tuning, which is not machining an LSD. The transfer case is already quite stout, and there's the twisted insert available to reduce slop a bit.

The best anyone could do would be to buy up some junked front diffs to tear apart and get sizing and the welded/bolted stuff clearly sorted.
 

shushikiary

Sergeant
Jun 4, 2018
304
173
0
Ride
335xi
There is a known quaife part number, but I don't want to post it here as I find that impolite to the purpose of this thread. If you want it, either PM me or email Birds auto.
 

Cheezy

Lieutenant
Nov 7, 2016
611
225
0
Toledo Ohio
I have a bolted sample I can send in. I'm just waiting for @Twisted Tuning to give instructions

20190922_231311.jpg
 
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Cheezy

Lieutenant
Nov 7, 2016
611
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Toledo Ohio
@MFactory
@Twisted Tuning
I also just realized that this diff is out of an auto car. The casing is marked in 2 different places as being 3.46. Thus meaning I have an oem bolted auto front diff that can be sent in for measurements
 

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shushikiary

Sergeant
Jun 4, 2018
304
173
0
Ride
335xi
And now things just got even more interesting.

That means that there is a cross over date for auto's likely. Usually they go from bolted to welded (its cheaper to weld them) rather than from welded to bolted.

Do you know exactly what vehicle that came out of and what the build date was?

At a minimum this makes me wonder if the auto guys could source a bolted front diff for them selves and then swap to the LSD carrier and then no one has to have gears made.