I have a MTD Lawn Tractor it mowes fine if you use 5th or 6th gear, but if you use any lower gears it doesn't pull. Anyone know what could be the problem? I've downloaded the owners manual and thought it would have a clutch, but can't find one. Any suggestions?

You will have a linkage for the clutch, but I would think it is internal. This is one of the things that is hard to diagnose on the net.

Thanks for the answer. My lawn tractor just quit pulling. I was hoping for an easy fix, but the belts look good. Now don't know what's wrong.