Thanks for the replies, to be perfectly honest.... I don't know what model trucks I have.
I have one truck that has a Holden Id plate with a body S104 and model M15843. So, at this stage iam goi g to presume it was assembled in Melbourne on the 15th of the 8th 1943. I also have what I believe is a 41 American built wooden cab chev truck which apart from the wooden cab is an identical item.
If I compare tyre sizes and number of spring leafs using the gmheritage documents, I believe they have a gvm of around 10-120000 pounds.
It seems to me that the cabs and chassis are identical r through the size range, only the brake and suspension packages change along with gear box and a strengthening plate along the chassis rail over the 1.5 ton truck.
I have been getting cab parts from Chevy of the 40's and Jim carter. It is nearly time to have a look at the brakes and neither of these places list replacement parts for brake drums, they list for the smaller pick ups but not for these bigger girls. Iam not too stressed about the wheel bearings as such Mostly looking for replacement drums and inner wheel seals(they look to be a stemco type seal)
According to the gmheritage centre the ratios are in the 2 speed diffs are either side of the single speed units, so, at least in high range it should be faster then a single speed unit.