[chilledn52]

Been looking around for anyone else who has done a front and rear differential swap as I'm trying to get a total list of the parts needed. I know the flanges from the auto and manual are different but unable to find much information of front differential swaps.
Current Diff - 3.38, Auto Xdrive Diff - 3.91

Current Idea of Parts -
Auto 328xi front and rear diffs
Auto 328xi rear CV axles
Auto 328xi rear driveshaft / flange

[Leucosticte]

Originally Posted by chilledn52

Been looking around for anyone else who has done a front and rear differential swap as I'm trying to get a total list of the parts needed. I know the flanges from the auto and manual are different but unable to find much information of front differential swaps.
Current Diff - 3.38, Auto Xdrive Diff - 3.91

Current Idea of Parts -
Auto 328xi front and rear diffs
Auto 328xi rear CV axles
Auto 328xi rear driveshaft / flange

So I didn't do exactly what you plan to do but I manual swapped my 328xi. From what I know all you need are the diffs. The CV axles, driveshaft, and flange should be identical. For xdrive cars the auto/manual versions share the same driveshaft.

Keep in mind that with the 3.91 your gearing is going to be very short. For example 3000 rpm in 1st is about 10mph, so you have to shift often. It's a lot of fun but if you don't like high rpms at highway speeds then it's probably going to be best to keep it stock.

Hope this helps, also I thought stock xdrive manuals were 3.23 and not a 3.38 ratio, maybe I'm wrong.

[Runnin'Rich]

Are you sure it's not going to be overkill?
The xdrive 6MT is geared pretty high already.
This is so you can crawl up a dirt road in 1st without stalling.

[chilledn52]

Originally Posted by Leucosticte

So I didn't do exactly what you plan to do but I manual swapped my 328xi. From what I know all you need are the diffs. The CV axles, driveshaft, and flange should be identical. For xdrive cars the auto/manual versions share the same driveshaft.

Keep in mind that with the 3.91 your gearing is going to be very short. For example 3000 rpm in 1st is about 10mph, so you have to shift often. It's a lot of fun but if you don't like high rpms at highway speeds then it's probably going to be best to keep it stock.

Hope this helps, also I thought stock xdrive manuals were 3.23 and not a 3.38 ratio, maybe I'm wrong.

3.23 are for the RWD models 6MT.

Its would be one of the last mods I do looking do as I'm pretty much full on bolt besides headers and MILVS. More looking for DD and looking for a bit more torque around the city, still fully considering to do or not.

[chilledn52]

Originally Posted by Runnin'Rich

Are you sure it's not going to be overkill?
The xdrive 6MT is geared pretty high already.
This is so you can crawl up a dirt road in 1st without stalling.

Its an idea at the moment but it would be same gear ratios for anyone with AWD who did a manual swap.

And yes plenty of torque in 1st

[Leucosticte]

Originally Posted by chilledn52

3.23 are for the RWD models 6MT.

Its would be one of the last mods I do looking do as I'm pretty much full on bolt besides headers and MILVS. More looking for DD and looking for a bit more torque around the city, still fully considering to do or not.

Interesting, realoem claims 3.23 for xdrive manuals and rwd manuals.

[e90yyc]

Hello from Alberta!

The 3.91 swap seems to be super popular. Like you, I’ve picked pretty much all the low-hanging fruit in terms of performance mods. Only things I’m missing are air intake, silicone intake hose, full exhaust… stuff like that.

I have a nice 3.91 rear diff that I would be more than happy to trade for your 3.38 if you’re interested?

I manual-swapped my car, but have always been interested in giving the 3.38 a try.

Leucosticte Yeah man: xDrive 6MT was 3.38

Not sure where in AB you’re located. I’m in Calgary.

I would be happy to buy your front diff as well. I don’t have one to trade in this instance as my original diff pinion bearing was noisy so I just replaced the whole front diff.

Are you sure the flanges are different? I don’t think they are…

[chilledn52]

Originally Posted by e90yyc

Hello from Alberta!

The 3.91 swap seems to be super popular. Like you, I’ve picked pretty much all the low-hanging fruit in terms of performance mods. Only things I’m missing are air intake, silicone intake hose, full exhaust… stuff like that.

I have a nice 3.91 rear diff that I would be more than happy to trade for your 3.38 if you’re interested?

I manual-swapped my car, but have always been interested in giving the 3.38 a try.

Leucosticte Yeah man: xDrive 6MT was 3.38

Not sure where in AB you’re located. I’m in Calgary.

I would be happy to buy your front diff as well. I don’t have one to trade in this instance as my original diff pinion bearing was noisy so I just replaced the whole front diff.

Are you sure the flanges are different? I don’t think they are…

At the moment I am good but I will keep you in mind when I do decide if I want to go ahead with it. What's your Instagram ill give you a follow!

[e90yyc]

Originally Posted by chilledn52

At the moment I am good but I will keep you in mind when I do decide if I want to go ahead with it. What's your Instagram ill give you a follow!

Sounds good! Shoot me a PM if/when the time comes.

I don’t have IG—conscious decision haha—but I appreciate the offer!

[Suvorovo]

Originally Posted by Leucosticte

Interesting, realoem claims 3.23 for xdrive manuals and rwd manuals.

I think MT 330xi and 325xi has 3.23. Mine is 3.23 feels really slow in first.