I have a 2004 Chevy HD with the Duramax engine (LLY version if it matters) and the Allison Transmission with which I pull a 5th wheel camper. We go camping in Tennessee every year (Fall Creek Falls State Park - Beautiful Place) and of course we have to travel up and down some steep mountains. The truck tows the camper without any problem except when traveling down a steep grade. Almost as soon as I start braking to keep from building up too much speed, the transmission automatically downshifts causing the RPMs to jump sky high, a few times even into the red. I know that the transmission is supposed to downshift while in Tow/Haul mode but it seems like it should allow me to slow down enough with the brakes before downshifting to keep from red lining the RPMs. I guess my question is: Am I doing anything wrong and will it hurt my truck if the RPMs jump up to the red area every now and then? In doing a little research, I have found some programmers/chips that claim to help with the downshifting problem. One even says "Virtually eliminates downshifting while towing". I'm not sure I want that, but if anybody has any recommendations on a good programmer/chip, I'd love to hear about it.
Thanks, Cory