[motto]

Lang. No, not a tipper.
I have a TM 10-1677 manual that covers models 4403, 4408, 4409 and 4412. On the cover of this manual below the large CHEVROLET title where the truck designation would normally appear e.g. 1-1/2 Ton 4x2 Truck,there is a strip of paper glued on that is printed in red and headed 'SPECIAL NOTICE'. It goes on to say that 'The 160" Wheelbase, Chevrolet Trucks imported by the Commonwealth Government for essential civilian users are equipped with:-
HEAVY 10" x 5/16"FRAME REINFORCEMENTS, AUXILIARY SPRINGS, 7" WHEELS, 7-7.50 x 20 TYRES and have an allowable gross vehicle weight of 14,300 lbs
With a tare weight of 5,488 lbs for the stake side body truck this gives a payload of just under 4 ton for what was initially classified as a 1-1/2 ton truck.
I personally have not seen a 160" wb truck without the reinforcement and it appears that trucks conforming to these specifications were also used by the military.
I thought this was an Australian adaptation but stumbled across a '42 Chev in Washington State (Port Angeles)many years ago which had the same reinforcement. It was identical to an Aussie L/L truck but LHD
David