Replaced the gearbox (dfq) last year and has been faultless (clutch, pressure plate and flywheel replaced)but recently now and again at low speed/revs while parking up get loud chattering/grinding last time it did it i put into neutral with clutch up but the sound continued for a few seconds then stopped then it's fine again for a week or two.
I would drain the oil and see what comes out,hopefully its not a broken diff rivet from crownwheel ,good luck.
Cheers watercooled just came home and the noise started again so shut the engine down but the noise continued for a few seconds after everything had stopped but could hear the fan running on half speed would appear the bearings in the fan are the problem I know I could just buy another fan but I always try to fix things like this can the bearings be replaced ?.
Everyone is possible, but splitting the fan and rebuilding it isn't really simple, and no doubt the brushes and armature will be worn too.