[DavidGitz]

I'm going to reference one of Al's posts:
-Put the robot on blocks: With power removed, manually rotate each side. Is there a difference? Does one side sound different? I assume you are using the stock Toughbox configuration, so the wheels should be fairly easy to turn and turn smooth.
-With the robot still on blocks: "Hotwire" (i.e. keep the main power removed and run a battery to both motors, observing correct polarity) each side again looking for obvious clues. If you have a DC Clamp (or some way to measure electrical current) measure current going to each motor. I believe with no load applied it should be around 5-8 Amps.

Other questions to ask:
-Did you grease the transmissions? Did you assemble them correctly? We've had problems in the past with the Toughbox transmissions with the lock washer (don't know the correct term) that holds the gear in place coming off and getting stuck in another gear. If you get any indications from the above that things aren't "perfect" I would take apart the Toughbox's and make sure everything is fine.

EDIT: Sorry, I didn't watch your second video till just now. It definitely sounds like your CIM motors are stalling. I would still go through the above tests to make sure it's not a mechanical issue. If those tests look fine, there might be something in your programming going on. But it sounds like a mechanical issue to me.

My $.02

Another Edit: That sound is not your CIM's stalling, I don't know what I was thinking last night. If the CIM's are stalling there will be a lot longer pause between the sound as the breaker will have to reset and that will take about 1-2 seconds. It's definitely something binding or stuck in the Toughbox.