well my bad if the motors at the wheels are electric, I was figuring they be hydraulic,
in that case, there has GOT to be some way for the controller to know it was -not- going in a straight line, so it would cut power to the inside wheel on a turn
a steer sensor card or switches.

Thanks,
I will check all my solenoid wires. This unit drives with 2 electric motors at each back wheel contolled by a motor controller. I think there are 2 manifolds.... lift and steering. The more I turn the wheels left the faster the unit goes... I checked all wires in the control box on platform and everything there looks good. I will continue on tuesday my next day back to work.

ANY OTHER IDEAS???

I am not sure where it is in your truck, but these units should have a hydraulic manifold in which there are a reversing valve and a differential valve (there may also be some speed control solenoid valves there also). I am betting you have the wires crossed on the negative sides of the solenoid coils for these valves.
you may be able to figure out where these valves are by following the hoses from the drive motors at the wheels back to where they go into a hydraulic valve manifold.