it has an sm420 manual 4 speed tranny in there (in need of a rebuild)
the highest my revs go is maybe 3000 unless i am really pushign it....it is scary up past that many rpms in there though....it really doesnt even need to go much past that becuase my usual crusiign speed on the highway is 2000 rpm at 70 mph....which is pretty darn good in my opinion. hell it will climb hills in 4th gear at 1000 rpm with no lugging...its got monsterous torque and awesome gearing.
anyways, back to the matter at hand...i will most likely make soem sort of fan shroud, and keep the electric fan as a pusher so that while im offroad ad idlign really slowly i will have some air flowing...as well as have it kick on when the truck is off to keep the temps down. i guess bottem line is ill just have to experiment.