I'm sorry, my guess of final drive ratio of 4.9 was too low. It has a 3.9 diff, 2.0 planetary hubs for 7.8 axle ratio, times 0.78 (http://www.allisontransmission.com/i...ies/3700sp.jsp) 7th gear ratio = 6.08 final drive = almost 2700 rpm at 60 mph - really winding the Cummins out past its' peak efficiency. 50-55 mph would give one better fuel economy and is a fine speed for anywhere in the world except US interstates.
Last edited by charlieaarons; 05-02-2012 at 02:51 AM.
Unimog U500 with Unicat camper; diesel BMW X5 35d, diesel BJ40 Landcruiser and diesel M37