I have a 84 dually that PO swapped the 4.56 gear for he said a 3.54, but I'm thinking after a tow the other day its even higher. My Q is, I have a Military single 14 bolt with 4.56 (should be), are they the same 3rd member? Also, if memory serves, can't I just pull 3rd member n not have to setup gears PO at same time of gear swap had shop put a NV4500 n, so I don't see any prop with highway running at 80? anyone running 4500 with 4.56 on 265/75s 5th at present is pretty much worthless, truck has 6.2L with banks kit. thanks, - - - Updated - - - I know, its a carrier, not a 3rd member, but still, no one going to say anything ???