Digga,
I have a 1950 Chevy COE, model 5700. It is referred to as a 2 ton model by the factory. The cab and chassis weighs 6500 pounds and with the bed and hydraulic lift it weighs 7500 pounds. The gross vehicle weight (GVW) stamped on the identification plate is 16,000 pounds. Clearly it can carry much more than 2 tons. The heaviest load it has carried since restoration is when I was the designated driver for my two adult sons and 25 of their friends when they wanted to visit Whiskey Row in Prescott, AZ. That load did not even touch the overload springs.
I have a 2 speed differential and the housing is different than the single speed. I don't know how to judge reliability based on a single unit but it functioned fine when I got the truck, which had been worked hard on a farm all of it's life. It did need new spider gears which were not easy to find.
Regarding brake components, etc, brake cylinders can be resleeved and brake shoes can be relined. The seals, cylinder kits and such will require you to develop a close relationship with your local truck parts store where they greet you with calipers and a dog eared parts book, rather than asking what year your vehicle is, while poised over the computer keyboard.
Good luck and welcome to Stovebolt,
Kent
