Rookie Diesel Owner
Posting this for my hubby: I recently bought a 2014 GMC Duramax Diesel. Previously pulled With a big block Chevy. Not sure what gear to use when pulling: Drive or Manual and I am not sure about th...
Forum Discussion
I have the classic 2007 GMC Sierra SLE 3500 dually. Most of the time I just put it in Drive and let the Duramax/Allison do what they do best. However, in the mountains of Colorado, and on a recent trip in October at various elevations up to 11000 feet, I selected Manual mode and chose my gears, for going up and going down passes. If I went up a pass in 3rd, I also went down in 3rd (Wolf Creek Pass). Always in Tow/Haul mode.
