Truckstell made 2 speed diffs for Model T fords, I'm not sure who made them for the GM trucks, but I have seen one. It was in a '41 3/4 ton. That was about 16 years ago last time I saw it. Unfortunatly, the owner had an auction and sold almost all of the collection (mostly parts cars) exept for 1 '41 1 1/2 ton stake and a '55-'57 school bus. I beleive that those have since been sold as well.


Bill Burmeister