It isn't the exhaust. Pushing clutch erases problem.
I've had numerous hondas for 24 years. Initially it seemed to be a slam dunk axle problem, but the removal of torque removes the thumping. the thumping is in meter with wheel rotation as it becomes faster with speed. The only thing I can remember is that while driving in snow recently, acceleration caused the tires to "hop". I quickly let off the gas and can't imagine that this was a cause/affect situation. Any thoughts?