Shasta,
I have exactly the same problem with my Troy-Bilt 6.5 hp mower. I don't see any answers to your question and wondered if you had found a resolution to the problem. If so, please e-mail me at
[email protected] or on this board. I would be very grateful for the help. Mine appears to have been put together slightly out of line which has caused the front left wheel to have the plastic gears inside the wheel to be ground down. The right one is now beginning to be affected and is causing the mower to lose propulsion. I am afraid that replacing any one part won't correct the problem. It will only continue and begin to destroy any replacement part I add. Extremely aggravating.