624 has had two robots with very strong drive trains.
Our 2002 robot (Tankbot) pulled a car in a parking lot. Unfortunately there is no record of this. Here is the five wheeled tank in an unfinished state:
Our 2006 shooter robot had an unbelievable amout of traction (neoprene coated wheels, which ended up not being the best idea).
Here it is pulling Kyle (~135lbs across carpet, low gear, full contact).
In addition,
here it is pulling Mr. Pramik, one of our mentors that year (~250lbs across carpet, low gear, full contact).
Those might not be the same as pulling a truck, but there is a whole lot more friction to overcome.