Minty had this acceleration clunk going on recently, and I checked the mounts and they were okay, driveshafts were okay, no misfire or anything like that. Today I was over at
@CamZH's picking up some parts and he mentioned a rubber pad that sits on the subframe on the passenger side, and sure enough on my car it's missing! Volvo part #3507606, Item #3 in the below diagram:
This was giving the engine a lot of room to wobble left/right, and the bottom of the gearbox was banging on the subframe where the pad should have been. Cam happened to have a spare subframe lying around, so we pulled one from that and installed it, and the vibration is basically all gone. I think it might have been rocking around so much that it's damaged the right hand mount (the one below the timing belt) so I'll check that soon but otherwise the issue is largely resolved.
