Transfer case issues on these are not uncommon, particularly if the gear oil hasn't been changed according to schedule, or at all. I experienced similar symptoms. What's the oil condition like Any metallic flakes when you checked it What kind of driving do you typically do Short trips, long motorway runs Also, has the gearbox ECU been scanned for fault codes

I haven't checked the oil myself, to be honest. I do mostly city driving, short trips, stop-start traffic all the time. I also had the ECU scanned, and it showed a 'transfer case oil wear' error.

Okay, short trips and the 'transfer case oil wear' code together definitely point to the transfer case. The oil is probably knackered and the gears might be suffering. I'd suggest taking it to a specialist who knows these cars well. They'll be able to give it a proper assessment and advise on the best course of action.

Update It was indeed the transfer case oil wear fault, as suspected. Gears had excessive wear. I ended up paying 330€ to get it sorted. Thanks for your help

Ik trek hier mijn haar uit. Mijn Mini Roadster diesel uit 2015 is begonnen met problemen. De versnellingsbak voelt aan alsof hij slipt en de schakelingen zijn echt onzuiver. Ik vermoed dat het verband houdt met een versleten transfer case olie, en dat de versnellingen defect zijn. Heeft iemand iets dergelijks meegemaakt?

Mini Roadster Problemen met de Versnellingsbak