Nice!!!!! So I’ll get some differentials from a 4.4 and just take the Flanges for the axles from my rear diff to the 4.4 to make the swap complete in the rear?

I'd look at the GS6X37BZ/DZ gearbox (BMW part# 23007563053) used in the late e46 iXs. The e46 shares the same 5-speed trans with the X5 and never received X-drive, so there's a high likelihood your old transfer case will bolt up. The e46 used the same transfer case its whole production run as far as I can tell.

This is when I give AMG’s a hard time.

This is a great thought. I just did some poking around on realoem, and it appears the e46 ix transfer case is more like the x5 lci atc500. It's a similar bolt pattern but doesn't look to be an exact match from what I can tell. I think the e46 is slightly different because of packaging (i.e the front driveshaft is more tucked in than on the e53). The pre lci x5 tranfer case (nv125) will definitely not bolt up to the e46 trans. Possibly, you could put the e46 transmission, front driveshaft and front diff in the e53, but the differential ratio would be different than any made for the e53.

Thanks for the idea originally but I want the 6 speed and I was thinking to use the 6 speed transmission from the e46xi but I have really checked out the part numbers.

Yeah, that was my point. Here's my logic:

The 5-speed is shared between the e46 & e53 3.0. The e53 LCI transfer case bolts to the 5-speed (although e39_touring says the pre-lci xfer case doesn't) and we know the e46 transfer case (nv125) bolts to the 5-speed. We also know the nv125 bolts to the 6-speed used in the e46 so it follows the nv124 should bolt up as well, so that 6-speed should work in an e53, in theory. You might need to figure something out for the shift linkage but I'd imagine it will be close if it doesn't work out of the box.

Even though the transmission is the same family, the ratios and cases are different between the E53 (nv125 t/c) and E46 (nv124 t/c). I pulled a couple of pics off ebay (nv 124 on top), and the transfer cases do have different bolt patterns and axle configurations, making a swap like this very difficult and involved.

Heyyyyy. Bringing this back from the dead……

jps /...do you have an update? Did you ever swap diffs or install a 6-speed trans?