Mike, I found an old Hollander. It doesn't list a 1 ton Chev, but it does list GMC. 1 ton GMC used the same rear end from 41 to 48. They came in 4.12, 4.86, and 6.67. The same third member shows to fit a 40-47 Ford and a 48-52 Ford. The fact that it interchanges with Ford leads me to believe that this would have been an Eaton.
