08 2500hd 6.0l - Tranny Questions, Possible Issue?

[dcontarino]

Just got the truck two weeks ago, gone 800 miles so far. I love it so far, especially how smooth the 6-spd tranny is. Yesterday, I pulled out of my driveway and drove down the street, and the truck snapped from 1st into 2nd gear - a very rough shift and a huge drop in RPMs, and not characteristic of the shifting at all so far. This continued for my entire trip across town, and only when tranny was shifting from 1st to 2nd. On the return trip (after turning the truck off and back on), the shifting was back to normal - smooth as butter. Is the jerky shifting on that trip something I should worry about? This is my first GM product so I don't know what is normal and what isn't. I know the tranny computer "learns" driving styles, so I'm hoping that's all it was...

 

Another comment/ question on the 6-spd auto tranny is in regard to kickdowns. When travelling at about 45mph+, in 6th gear, I've noticed that in order to get some passing power, I need to push down pretty far on the gas pedal to get it to downshift. I would have thought that with 6 cogs, the response would be much better than a 4-spd auto, which I'm used to driving, but not so here. When I press down far enough, the tranny finally downshifts, but then the engine snaps up to 3000 rpm+, so there's too much power for some situations, especially when driving in the city. I'd be curious to hear from current owners or experts whether this is normal or something to be worried about.

 

Thanks

[lord-dogbert]

Mine does that close to freezing, it's some cold weather feature for better heating or something like that. Not sure if this is your scenario but i'd log a case with the stealership.