Allison 6 Speed
[Chuck] Economy mode controls shift times going thru the gears, shifts at lower rpms, if no strain.. Keep in mind that 5th and 6th are overdrives in this trans. With my Cat(330) the fifth will keep rpms at about 2100, "sweet" spot on the torque curve, and a great uphill pull. Don't be afraid to shift down, even better do shift down. The Cat runs/pulls so well we tend to get lazy. If you push the buttons and keep around 2000 rpms your engine will be much happier pulling. You should have gotten an Allison manual with some of this, some just comes with experience. If you try to pull in the Rockies at lazy rpms 16-1700 you will probably overheat. Happy Trails...