I've long held the theory that the 1-tons were a creation of the GM marketing department. This is my speculation:
Marketing and Sales told Engineering and Development that they needed a heavier duty pickup than the 3/4-ton to compete with I-H and Diamond T but it had to be cheaper than either. So engineering went to the parts bins and came up with the 1-1/2 -ton 137 inch frame and suspension, including the 4100/4400 front springs; the rear springs are 2 in. rather than 2.5 in on the 4100 and bigger. Then they made a 9-foot box to fit the longer frame. The Eaton HO 72 rear axle was plenty stout but needed bigger brakes. So they bought 14x2-1/2 brakes from Huck specially for the 1-ton and used the 3/4 ton front axle. They took the rear brakes from the 3/4 ton and put them on the front of the 1-ton. Then a heavier gauge spring-steel bumper for good measure.
Voila! Heavy-duty pickup; basically a 1 1/2 -ton with lighter axles. Combined gross axle weight is 3500# ft, 7200# rear; totaling 10,700. The limiting factor is tires. Nameplate says 8800# when equipped with maximum tires.
The oldest of these I've seen are '46; Deco cab, 9-foot box, same running gear except for crash-box (SM420 trans came in 49, I think.)
But for the engine, nearly impossible to wear out, brakes that last well over 100,000 miles, a cab and sheet metal that rarely cracks even on rough roads, though radiators leaked on rough roads; can be overloaded till the axle pads hit the frame and then some. Order the hydrovac or use both feet on the brake pedal and forget lifting weights at the gym, the steering wheel takes care of that. I've loaded mine with 4 tons of rockery rocks, 2 yards of topsoil, two yards of gravel, a full chord of wet alder and in nearly 50 years replaced one rear wheel bearing and one front wheel bearing, oh, it's working on its second set of brake shoes but the drums are nearly worn to the limit. Other things are modifications I made to go faster.
