Driving with the Allison Automatic Transmission

I drove transit coaches with Allison 5-speed and 6-speed boxes for nearly three years. I never tried to out-guess Allison's computer - it seemed to be a lot smarter than me, even though I'm a B.S. (Mech. Eng) guy.

If you're renting and not familiar with either diesels or Allison transmissions, my advice would be to put it "D" and let the computer take care of things. You could screw things up trying to out-guess the Allison computer.