as far as transmission issues in those years all the transmissions have issues----it is just part of the animal-----the nv4500 is the cheapest to fix---followed by the automatic at $3000---the nv5600 is the most expensive----the truck you are looking may have already had the clutch done---if you need syncros it will run about $700 at a tranny shop---5th gear fix maybe $350 and it can be fixed on the truck------after all this talking-- that truck may already be sold.....