It seems to be a problem with the gears, this is what shows in the garage. Don't mind the actual numbers, I'd clicked the arrows quite a bit by that point without any effect:
Some have reported that substituting the trMini_lhd_gears.ini fixes the problem, though the only difference I can see between that and the trmini_gears.ini is that lhd has ratios along the lines of 10000,32000 and the normal one has ratios like 100,320. Same ratios, but put in a different way. Seems a bit weird.