Might Help - I teach my students to use the MPH as a guide when down shifting and not the tach. Example is if your slowing from 60MPH to exit - once you hit 45 you should be in 9th (4+5=9) then at 35 you should be in 8th (3+5=8) at 25 you should be in 7th (2+5=7) - you get the idea. Works well for upshiting and the new trucks have progressive shifting and it really works for them.