</font><font color="blue" class="small">( I watched my son drive down once and I notice the one wheel trying to back up while the other went forward. )</font>
Murph, I'm certainly not an expert on our differentials, but I'm wondering if your one wheel reversing might have something to do with your problems of getting the differential lock to release properly?
Also, if you've ever had a car jacked up in the rear with both wheels off the ground and the transmission in gear so the drivetrain won't move, you can rotate one wheel and the other one will rotate in reverse. If you are going downhill and your tractor is in low range on the hydro, it might be that the drivetrain can't turn easily so one wheel with the lowest traction will actually turn backwards. If traction was exactly equal, I bet both wheels would slip. If you put the transmission into a higher gear, the drivetrain will cause the hydro to attempt backpumping a little and let the drivetrain rotate so that both rear wheels can turn.
This is just a "gut" feeling based on what I've seen with drivetrains and realizing that it's almost impossible to make a hydro drivetrain backpump. That's why when you lift the pedal, the tractor stops on a dime without braking. What do you think? /forums/images/graemlins/confused.gif