BMW X-Drive Front LSD Differential

[shushikiary]

Manual or automatic make no difference except getting the correct gear ratio.

Being a N55 however does make a difference. The front diffs on the N55s are different. I know the case is different, not sure the carrier is different. So I doubt this lsd would work for a N55 powered car. But correct me if I'm wrong. (Note all the 435's are N55 powered)

 

[scrllock]

Manual or automatic make no difference except getting the correct gear ratio.

Being a N55 however does make a difference. The front diffs on the N55s are different. I know the case is different, not sure the carrier is different. So I doubt this lsd would work for a N55 powered car. But correct me if I'm wrong. (Note all the 435's are N55 powered)

Motor doesn't matter, ratio, ring gear type, and housing size do. The mfactory rear diff I have is also for N54 platforms. People really need to post the full year, model, and trans type if we can even get solid info on the bolted/welded question.

 

[shushikiary]

Yes but that means motor matters. Because the front diff bolts to the oil pan, when the oil pan changes, the housing changes. There are vastly different part numbers for N55 powered 335's vs N54 powered 335's (between E90 and F30) for the front diff. The E90 N55 powered cars on real OEM seem to have the same part numbers, but when I call the dealer they are different.... so the whole thing is strange.

For a 435 however, given its an F series chassis, the part numbers for the front diff are very different, even the gear ratio is different it seems. 3.23 for the manual and 3.15 for the auto?

 

[scrllock]

Not true, you're assuming the oil pan is specific to the motor, when it's specific to the chassis/xdrive combo. In fact the oil pan on my N55 e90 is shared with the xi n52 and n54 e90/e92 (and e84), and the front diff carrier is not only shared with the n54 e9x's, but with the 5 series too(which has a totally different oil pan part #).
Even then, this isn't a group buy for a full pumpkin, just the lsd, and it's quite possible that even with a different part # for the carrier on the 4 series, the diff itself is compatible.

 

[shushikiary]

Yes, and I stated that... let me quote my self:

Manual or automatic make no difference except getting the correct gear ratio.

Being a N55 however does make a difference. The front diffs on the N55s are different. I know the case is different, not sure the carrier is different. So I doubt this lsd would work for a N55 powered car. But correct me if I'm wrong. (Note all the 435's are N55 powered)

So thank you for agreeing with me that the carrier my still work in that housing, as I said, I don't know that it wont.


What's confusing to me is why the dealer has different part numbers for the N55 powered E90's front diff then real oem. As far as the F series front diffs, we'd need people to pull some and see if they are welded/bolted (because of the difference in gear ratio yet again compared to the E series, and even then if the pinion changed it might have a different offset because the housing changed, so its possible using a set of gears even on the same carrier from an E series, if bolted ring gear, might not work), and then we'd need to see if the carrier is the same or not.

 

[scrllock]

Thanks for editing your post to clarify. Just don't want to discourage people

 

[The Banshee]

Any plans to move this forward?

 

[Maniac0908]

I hope so....

 

[Cheezy]

Yeah we just need to gather information.

 

[Maniac0908]

Yeah we just need to gather information.

What do we need?

 

[Cheezy]

Ok re-reading that several times, just to make sure I understand...

1. We need to find someone with a bolted sample to send them.

2. We need to figure out how many people in the group are manual vs auto, we know for sure the rears are different ratio's, and given the transfer case needs front and rear tire size to be within 1% I'd say that's hard evidence the front and rear are very likely the same ratio (not sure I've ever seen a transfer case that allows different front and rear diff ratio's).

From there, we need to figure out if everyone is willing to pay for new gears, even if they have a bolted diff, or else we don't have the 20 no matter what, but if we have 10 bolted diff's on the list they could still get an LSD made.

Then, once we know if the majority is auto or manual (likely auto) are enough members of the minority willing to switch out both their front and rear ratio's to get to 20?

To me it sounds like we REALLY need to figure out how to identify if a car has bolted or not by the VIN / build date or something similar. We also need people to state if they are manual or auto.

Obviously I'm manual as already stated.


Ok so from http://www.realoem.com/bmw/enUS/showparts?id=VD53-USA-04-2008-E90-BMW-335xi&diagId=31_0718

So it seems the auto and manual have different part numbers, and look at "i" it shows 3.08 or 3.46, so we KNOW for sure auto and manual have different part numbers, and thus the ratios. This is for an E90 no LCI update. Note the E60 part numbers are the same.

The LCI update cars seem to have the same part numbers? But there's a comment on part numbers from build date 08/2009 for the auto transmission cars.

That starts to give some interesting hints that we might be able to tell welded vs not welded (and obviously gear ratio) by part numbers...

What do we need?

 

[Maniac0908]

Well.... I can take mine apart. Is knowing if it’s bolted or not all we need to know. Only thing is I can’t send them my diff as it’s my daily. And I’m auto but going manual in a month

 

[Maniac0908]

Hopefully this helps a little?

 

[shushikiary]

From your posts I can surmise you're an auto (but going to do a manual swap later), can you give what model and build date your vehicle is? Then we can add that to yet another data point of being a welded diff.

Also, looking at that.... how the heck do you set the bearing pre-load, pinion depth, and backlash? I don't see any shims or nuts to torque down that would do that... does one not even pattern the gears after an install? lol

 

[Maniac0908]

From your posts I can surmise you're an auto (but going to do a manual swap later), can you give what model and build date your vehicle is? Then we can add that to yet another data point of being a welded diff.

Also, looking at that.... how the heck do you set the bearing pre-load, pinion depth, and backlash? I don't see any shims or nuts to torque down that would do that... does one not even pattern the gears after an install? lol

E90 335xi 06/07

 

[Maniac0908]

Do you guys think putting some addictive like lucas or something would help?

 

[Twisted Tuning]

Hopefully this helps a little?

your pic looks identical to the one @Cheezy sent me. His is an AT Xdrive too. Chad, what year is your car again? build date?

 

[Cheezy]

your pic looks identical to the one @Cheezy sent me. His is an AT Xdrive too. Chad, what year is your car again? build date?

That diff was from a 2009 535xi 6at. Build date was 09/2008. Last seven of Vin is C132280. Car is totalled, parted, and scrapped, so I'm not concerned with sharing the VIN haha. I have another front diff that I'll be disassembling soon, but I'm having a little trouble getting a Vin from the seller, to match it to a build date.

 

[shushikiary]

@battlehawk and @Reaper0995

Can you guys give the build date, transmission, and model of the cars the pictures you posted were from? I know we have some info on auto/manual posted for them, but having 4 data points (cheesy, battlehawk, reaper, and maniac98) would be useful.

So far it seems any auto from before 09/2008 is welded (from maniac98 and cheesy).

I'd love to get some manual info. I guess I could pull my manual front diff apart at some point in time... giant PITA... Maybe I could just stick my endoscope through the drain hole (can't use the fill hole, the pinion would be in the way).... Wish I had known back in july when I replaced my turbo's and had the whole oil pan with the front diff on the floor... lol.

 

[battlehawk]

2007 335xi 6speed manual. 3.08 gears. Front was a bolted diff. Rear was a welded. My car was built in may 2007.

A front bolted , manual trans LSD already exists. See my previous post about the part number.