My wife has a 2012 Countryman w/ manual trans. +/- 80,000 miles. It has developed a horrible crunchy sound like rocks in the gearbox and only makes the noise while moving in gear. Coasting in neutral makes no sound at all. I assume the internal bearings have gone out. I can’t find anyone that rebuilds mini manual transmissions, so we’ll have to replace the gearbox. I plan to replace myself, and am capable of doing so. I’m having a hard time finding base 6 spds anywhere near me but there are plenty of S model 6spds available. Are the two gearboxes interchangeable? Can I put an S 6spd in a base R60? I’d greatly appreciate any insight you guys could offer!