Thanks for the help
one brush was stuck so bad it came out in pieces. I cleaned the come and replaced the brush. The other brushes were ok. I also found the F1 cable shorted to frame ( from the other motor) pinched under a plate at the back and almost completly broken. add to that, the cut out switches were out of adjustment. By the time I picked the melted copper out of the comm I still had 8 hours in this. At least I didn't have to take the the truck apart.
Thanks again, I like to let people know they're advice was worth while

What is the serial #. If it is a later model with a serial # that starts with 324......then it is a fairly indepth job. You must remove the mast, unbolt the drive units from the frame and then separate the motors from the drive units.

i don't know this model but other stills. you have to take off the mast remove complete front axle complete. then strip motor out