08 lmm tap shifter

[gspman]

Hey Folks
This is my 1st post on this site, I just bought a 2008 2500HD with the duramax engine and allison trans with 37k on the clock.

I am kinda confused as to how i can use the tap shifter and the benefits of doing so.
I am hoping some of you might be able to set me straight.
1) Can I shift from Drive to Manual at,,,, say Hwy speed ?
2) If i have the tow/haul activated , will i have engine or exhaust braking?
3) If i am in manual can i tap into drive..aka od?

Thanks much in advance

[tbrowne]

It's in the owner's manual but yes - you can move the gear selector to manual at any speed and the trans will stay in the same gear you were in. Then you can shift manually to any other gear you desire. I've used it, but the trans generally does a better job shifting than I do. The trans will shift down on grades when in tow/haul mode and use the engine to help with braking - assuming you're not in manual mode. It works very well under most conditions. There is no exhaust brake on the 7.5 through 10 models unless you have a tuner that provides the feature.