Don't let GR worry you about power issues. My friend has a 2000 CH613 with the 460 and 18 speed. He brought it out to my farm a couple years back, pulling a 50 ton trailking detach and a kobelco 210. He was able to up shift pulling the hoe/trailer going up some very steep hills. This was off road in the soft pasture. So you will have no power problems. Macks have very good torque and that is what gets it done. If you have any questions/problems let me know.