GVW is actually truck, fuel, people and payload, the GCWR is the truck GVW + allowable towed vehicle GVW, so the 6100 could pull a trailer that had a total weight of 11000
Bill
Actually the trailer could weigh more assuming the truck wasn't already loaded to GVWR before adding the trailer. Let's assume it is set up as a tractor. If the truck and all necessary equipment, fuel, driver, etc. weighed 12,000lbs, for example you could pull 20,000 lbs. The GCWR is just the total weight rating for truck and trailer combined. Of course you still have to consider the weights on each individual axle.