BMW X-Drive Front LSD Differential

[shushikiary]

Interesting, further proof that the front being welded does not fallow the rear being welded.

Now I really want to check mine and see if its bolted. It would be AWESOME if all the manuals are bolted, because then we could have a gear set made for the auto's, but all the manuals can just swap over their gears.

I wonder if Bird could give more info on that, I'll shoot them an email (given they already do the quaife helical LSD for the front).

 

[Maniac0908]

Ok so from what I’m reading, there is a lsd option for bolted front diffs only. But they lack in pinions? Sucks for us welded guys. Unless we were to source a bolted front diff and swap. Are we moving forward with this. I feel like 30k to r&d and produce these is enough lol

 

[shushikiary]

Ok this is interesting... Bird got back to me and they said that the Quaife QDF21N diff would fit, which is for a X3 diff that goes in both the E84 (x1) and the F25. They also did not require that I do the swap, which suggests they somehow know which ones are bolted and which are welded (on their website they say you have to do a swap with them of your diff for a welded version).

I'll ask them if they know, and if they do how they know, if its bolted or welded. I think it would still be worth our time to get MFactory to make a gear set and diff, as then there is a source for front gears other than junk yards (for bolted ones, and so far there doesn't seem to be a bolted AT gear set), and once they are setup to make one ratio it wouldn't be that hard to setup to make another ratio. The more cars we find share that gear set and ratio too will help in making it a good idea to make it.

 

[shushikiary]

Good news everyone!

Bird confirmed that all diffs with 7575785 are bolted (the last digits of the part number). This means all manuals should be bolted! This is confirmed with VAC and with BMW WEBetk.

Bad news... I can't find jack about the auto's. But our data so far suggests that all the auto's are welded (remember referring here to the front diff for this entire post). So making a gear set in 3.46 seems to be the best bet.

 

[Maniac0908]

Ummm. So I dunno if this is the right place to ask this. But I’m putting back in my axle shafts and the driver side one feels funny. It’s in all the way. If I spin the differential(where front shaft connects to) it feels like it’s slipping. Is this normal?

 

[taron]

seems AT is 3.08, MT is 3.46 which actually is the same as for rear, considering our transfer cases has the same size gears for front and rear output.

 

[Cheezy]

seems AT is 3.08, MT is 3.46 which actually is the same as for rear, considering our transfer cases has the same size gears for front and rear output.

you're backwards on the at/Mt gearing. And we know the gearing has to correspond with the rear. The problem is in which ring gear type each individual vehicle has in the front diff. Welded or bolted.

 

[Btxbimmer]

P

Good news everyone!

Bird confirmed that all diffs with 7575785 are bolted (the last digits of the part number). This means all manuals should be bolted! This is confirmed with VAC and with BMW WEBetk.

Bad news... I can't find jack about the auto's. But our data so far suggests that all the auto's are welded (remember referring here to the front diff for this entire post). So making a gear set in 3.46 seems to be the best bet.

Where is the part number located on the front diff. I want to check mine out. If the quafie fits i may just go that route. Been waiting a year already

 

[Btxbimmer]

Ok this is interesting... Bird got back to me and they said that the Quaife QDF21N diff would fit, which is for a X3 diff that goes in both the E84 (x1) and the F25. They also did not require that I do the swap, which suggests they somehow know which ones are bolted and which are welded (on their website they say you have to do a swap with them of your diff for a welded version).

I'll ask them if they know, and if they do how they know, if its bolted or welded. I think it would still be worth our time to get MFactory to make a gear set and diff, as then there is a source for front gears other than junk yards (for bolted ones, and so far there doesn't seem to be a bolted AT gear set), and once they are setup to make one ratio it wouldn't be that hard to setup to make another ratio. The more cars we find share that gear set and ratio too will help in making it a good idea to make it.

Couldnt find a x3 diff in 3.46 idk how it would work.

 

[Btxbimmer]

If the manuals are bolted cant we go with the original 20 people they wanted for 1k total? Wasnt that the original plan of this post?

 

[Cheezy]

If the manuals are bolted cant we go with the original 20 people they wanted for 1k total? Wasnt that the original plan of this post?

Probably, but that would just screw all the auto cars. I'm thinking that this is how it's going to play out. You have the possibility of all bolted 3.08 front diffs for the manual cars. I think mfactory said they require 10 for that. Then possibility of bolted and welded 3.46 front diffs for the auto cars. Which they require 20, ten of each I assume. So maybe @MFactory and @Twisted Tuning can decide whether or not they want to move forward with the 10 manuals, assuming there are 10 manuals on the list. And then all the auto guys will continue to play the waiting game

 

[Btxbimmer]

Probably, but that would just screw all the auto cars. I'm thinking that this is how it's going to play out. You have the possibility of all bolted 3.08 front diffs for the manual cars. I think mfactory said they require 10 for that. Then possibility of bolted and welded 3.46 front diffs for the auto cars. Which they require 20, ten of each I assume. So maybe @MFactory and @Twisted Tuning can decide whether or not they want to move forward with the 10 manuals, assuming there are 10 manuals on the list. And then all the auto guys will continue to play the waiting game

Id hate to screw the auto guys but damn. We cant get 30. As soon as this product is actually out i bet way more people would buy it.

 

[shushikiary]

That's why they said the'd be willing to do 20 and eat the 10 I bet.

Really until everyone on the list says if they have a manual or not and what they are willing or not willing to do, there's no way we can tell what the proper course of action is.

Ok now here's something interesting as well, they did make an auto 3.08 gear set for this diff carrier.... the F10's had it.... So even if a 3.08 gear set was made it might actually work for some auto users as well.

 

[Btxbimmer]

Hopefully it gets off the ground soon. Awd is nasty at high hp/torque. And i plan on building the engine within a year.

 

[kylerwinters]

I'm wanting to jump on this but my engine blew so I'm not wanting to deposit $750 with no guarantee of delivery. I hope we get some sort of update or change of goals.

 

[Maniac0908]

Sooo, just put my car back together. I noticed a couple of things. First, for some reason when I spin the drive shaft, sometimes it will just spin and one wheel or both will barely spin or not spin at all. Other thing I noticed is when I spin one tire the other spins in the same direction. I always thought a lad spins same open spins opposite. Is something messed up?

 

[shushikiary]

More evidence that all the manuals are bolted... this is from an 01/08 build e90 335 xi manual.

 

[Maniac0908]

So I just blew my front diff I think..... my front driveshaft isn’t even connected....... anyway. I want to take it out and leave it out till we get a solution. Is it ok to pull both half shafts and diff and just run it like that?

 

[Jeffman]

If that happened to me I’d probably run xDelete to turn off the transfer case and to avoid any codes that could arise.

 

[shushikiary]

The two halves of the front wheel bearing are held together by the wheel nut on the axle shaft on one side pressing against the hub (which is pressed into the wheel bearing) and then the back side of the axle shaft against the other side.

If you pulled both axle shafts completely out you could literally have it such that the only thing holding the wheel on the car would be the disc brake caliper if the wheel bearing separated. Not only this, proper pre-load would not be placed on the bearing which would likely make it wear out much faster.

If however you chose to sacrifice two axles and pull the CV joint apart and leave the wheel bearing side half shaft in place, tear the boot off, clean all the grease/oil up and pull out the rest of the axle shaft from the CV, then on both sides, then pull the front diff off, and the passenger axle pedestal off, then somehow protect the hole through the oil pan as well.... then yes you could do it.