X1 N55 LCI, anyone done transmission or differential swap?

[chance91]

Hey everyone,

Looking to see if anyone has toyed with this yet. I've been looking for a while, and digging into the electronics portion of the 6hp and 8hp45 from the N55 and N20 and seriously considering trying the swap.

All I know so far is that the driveshafts are the same, and the differentials seem to be dimensionally the same, but I can not tell if the n20 front diff bolts up in the front.

Aside from that, the 8hp or 6hp in the e84 is locked to your unique ID, so cas/ews/dme need to be reflashed with the 8hp mechatronics to have your correct vin/id to work. Aside from that, I believe it should be possible.

Mechanically, you'd need an n20 flywheel to mate to the 8hp torque converter, or a different torque converter/flex plate to match.

Diffs should be simple swap and code, I hope. The 8hp uses 3.15:1 and the 6hp uses 3.64:1.

If I can't figure out the 8hp swap i may just do diffs.

Anyone have insight at all? Only a handful of people have pulled it off in any E-series but all seem to be running standalone ecms.

**So far, results of my search are that Front diff should work between any e90 xdrive and 2.0/3.0 E84. The rear diffs are "unique" to the e84, but I believe swappable as well.

[chance91]

So, I found out more about this.

Depending on your X1, you likely either have a 3.15:1 diff (N20), or a 3.64:1 (n55) diff.

Physically, either will swap into either car no issue. Axle shafts are also the same:
https://www.realoem.com/bmw/enUS/par...483&series=E84

They are also both 188LW diffs (as per the case cover). This is kinda sad but also expected as the 215L diffs were basically only in manual n54 cars and then a derrivative in M3s.
https://www.realoem.com/bmw/enUS/par...404&series=E84

The issue is the N20 diff is a 3-bolt driveshaft, but the N55 is a spline type rear diff/driveshaft.





So, while the driveshafts are the same length, the connection is different.

As well, the Transfer cases look very similar, but I can not verify at this time they are the same (different part numbers for sure.)

I still do not know about the front diffs. Considering grabbing one of the front. I did get a 3.15:1 rear from an N20 car for $60 so couldn't pass it up.

Lastly, I did find out how to code the 8hp45 from a similar/same year N20 to an N55, currently working that out. Basically, a number of people are using something like this to flash/clone modify these ecms. Found a professional who can clone the 6hp to the 8hp and load ews correctly.

Fun project, just think tanking it still, but the plentiful amount of X1 N20s in local pick-n-pulls makes this tempting/easy. Diffs so far are $100-200 each usually.