The original color for trans,driveline,springs, rearend would be new metal grey...soon to be dotted with rust depending on how soon you bought the truck after it left the plant.
I spose you could clear it with a dull or satin clear and make it look pretty close to original. That would be one way of retaining a stock appearance.
Any way you look at it...it left the factory as bare metal,which you have to coat with something or it will rust.
Dan
