HBM
I am assuming you have a 1/2 ton. The rear axle should be the same as a 54 to 62. That is a round 10 bolt cover with 3.90 gears.
As for the trans beyond what you already know, there is a later model 5 speed trans that was used in light duty trucks. It was used in GM and Dodge. I have heard, more so in the Dodge than the GM trucks. I think it is refered to as an NV something. Not much help I know.
