Hello everyone! This is my first post, so please bear with us. Namely, I have a wv polo 1.4 TDI 2005 before the lifting AMF 75HP engine. The problem is vibration / humming from 1,400 revolutions to 2,000,000 and this happens in every gear. Driving at 90 km / h in fifth gear it is unbearable, this phenomenon occurs both during acceleration and when braking the engine. I replaced all 3 cushions with new ones, absolutely no improvement, new driveshaft, no improvement, oil, filters. There was a lot of play on the differential, so I replaced the gearboxes without any changes. This engine does not have a dual mass flywheel. What do you think it can be because I already lack ideas. Could this be due to the torsional vibration damper on the clutch plate? At idle, in this RPM range, you can also feel trembling, but much weaker with the clutch engaged and disengaged. Please help.