if you're running tall rear gears the ZF I think is better,because 4th,5th,and 6th are close ratio between them. Not nearly as big a RPM drop. As far as the shifting goes,the pattern is a lot tighter.they dont shift like crap,IF you know how!

 

I am trying to make both the gear ratios in the HMMWV happy. It has 5 to 1 rear end gear ratio when in direct drive. and 2.56 to 1 when in high range. The gearing is fine; except when towing. The engine has been mildly hopped up to about 700 ftlb of torque. I am going to put a #10 plate it it, and a he351vgt ( mechanically actuated) in there when I get time. I would rather use the 451vgt, but there just is not the room.

It sounds like the ZF6 would be worth the trouble.