"Restore"; get it at the auto parts store. Add it with a new oil change. It's got copper sulfide, it will burn copper into metal parts, restoring compression around rings and the bearings. It's good the suspension is going; get dual zone fully adjustable shocks.
Yes, the trans idea is a good one. Add some undercoating to cut down on road noise mostly inside and outside wheel wells, use the fiberized stuff. You can get lots of awesome aftermarket parts for that truck. Just go to the store and pick up some 4x4 magazines,you'll learn a lot.
