if your truck has stock rearend than its gear set will inter change whith 49-72 3/4 ton gear sets
the only thing difrent between a AD 3/4 axle
and 67-72 3/4 ton axle is thay have upside down spring perches and narrower brake drums
4.56 gears and would cut your top speed a littel
but give you ****** hill climbing power
But you could add a over drive and fix that
