The wheel bases on the 34-35-36-37 1/2 tons are all the same however the prop shaft on the 1934-36 models is 52 1/2 inches long while the 37 prop shaft is 59 1/4 inches long.That is 6 3/4 inches difference. The 37 has a different design engine and transmission than the earlier trucks. The earlier trucks shared more componets with the master passenger cars while the 37 has a lot more stand alone componets.
