My Troy-Bilt self-propelled mower works fine with one exception, it will not back up. The mower is about 4 years old. The drive works fine, but the rear drive wheels will not spin freely and allow the mower to back up when I release the drive engagement handle. When I start the mower and begain mowing with the self-propelled drive it runs well forward; then when I release the handle to turn or back up the wheels will not spin backwards, they lock up and I have to pull the mower backward "skidding" the wheels. When I go forward again, they propel fine, but when I stop again (and again) they will never back up. Occasionally, when the mower has sat between mowings, it will spin freely forward and back, but the second I start it and the first time I engage the drive, the wheels lock again and will not spin backward. I've tried to adjust the drive cable so that the wheels will stop spinning when elevated; I tightened the cable and then backed it off to slow the drive and stop the wheels from spinning when free and not engaged, but no adjustments to the drive cable have helped. Do I have a problem in the drive axle or in the wheels or what? Thanks for any help, I thank you and my back thanks you.

Model #?

I have no idea of the mechanism. That's why I prefer front wheel drive.

What comes to mind is bearings, bushings or a clutch issue or lubercation issue.

There is a return spring missing on the engagement lever that pulls it out of gear when you release the control.

Hi,
The pin that serves as the drive pawl is frozen in the transmission shaft. This requires removal of the wheels, the drive gear and cleaning of the associated parts. Do not lube them except slightly as this can attract dirt.
Peace,
Clarke