I pulled both motors and tested individually. Both tested good with my dc transformer. I was really confused until I found a pinched wire between the motors which was causing an intermittent short. The insulation was missing in one spot and was barely touching a mounting screw. Depending on which way the truck swiveled, it would sometimes short out. What a pain! I don't think I would have found it without removing the motors. Good to know each motor tested ok on its own and they draw about 150-220 milliamps when starting. When running at a good speed they draw about 250 milliamps each.
I did notice one other thing. The in-series bridge rectifier in my GG1 is a gbu602. Its rated at 6 amps. The one on listed on Lionel's part site is a GBU802 which is rated a 8 amps. Since the patient is on the table fully apart, is it worth it to upgrade the bridge rectifier to the 8 amp version? Its a few pennies to get and its a no brainer to install it with everything gutted at the moment. I have no idea why mine has a lower rated rectifier in it. It was bought new from a dealer so I know no one messed with it before me.
