Vehicle has floor vibration and/or clunking noise in forward gears. May sound like motor mount is loose. No problem in Park or Neutral range.

Check rear transmission mount bolts for tightness. Bolts may back out and contact the crossmember causing the clunk noise.

For vibration, also inspect the motor mounts for collapsing (usually high mileage vehicle). This vibration can be miss-diagnosed as A/T torque converter etc.