I posted some questions over in the F54 section first, and was suggested I try here. Probably a good idea, since there are a lot more more Countryman owners...MINI seems to sell only a few Clubmans a month, these days.

I have a manual transmission F54 with All4, and recently the transfer box started leaking oil. Just a bit of oil on the outside of it, I think the seal for the main driveshaft to the rear differential is the cause. The car is under warranty and the dealer is taking care of things by replacing the entire transfer box.

My questions are mostly about "what about after the warranty is out/DIY", since there seem to be some other stories of these things developing leaks. My car has less than 30k miles on it, and a leak so early does seem suspect to me. I'd much like to keep my car going for a long time. So I bought the PDF shop manual to see how bad it is to remove/repair/reinstall, and it doesn't look terrible. The question arises though: the shop manual states that once a swap occurs, we are supposed to code the vehicle, but has no details on the procedure.

I guess my long list of questions would be: has anyone done a transfer box repair/replacement as a DIY in a 3rd gen All4? In particular one with a manual transmission? What was the process like? Was coding necessary? Did you end up swapping the whole case or just replacing seals? Also wonder if anyone has cracked open a Gen 3 All4 and seen the state of the gearing inside. I'm also quite curious about the differences between the manual version of the transfer box and the automatic version, particularly if an auto can be adapted/fitted to a MT, or if bolt patterns etc make this impossible. It seems fairly easy to find rebuilt boxes for autos, but the manual versions are only available new from BMW/MINI right now. To the tune of $3500+a core deposit. And since MINI stopped selling any All4s with manuals after 2019, they might be quite rare beasts indeed...

I did run into this old R60 video on youtube covering the procedure on the previous generation: . It looks like the 3rd gen removal and re-installation process will be quite similar. The end of the video shows a teardown of the transfer box with a fair amount of damage to the gearing that drives the rear wheels.

Anywho, if you've done it yourself, or even done it via a mechanic/dealer and kept apprised of juicy technical details about the process, I'd love to read about it.

 

Looking forward to seeing if you get any responses. I’m also curious if the transfer box fluid is recommended to be serviced. I’m guessing MINI would say it’s lifetime, like the transmissions.