[rames14]

Steve -
My understanding is that the braking is done with the Allison transmission control logic. I am not sure of the variable vane design of the turbo on the duramax. I will be over at my company's technical center and some folks from our turbo division will be there. I will try to get an answer on that. I do know that having my first diesel, it was strange to have the vehicle "control" the descent on hills without me doing anything. It sounded to me like a downshift. And, since my new Silverado is back with its former owner right now (Chevy takes 4 days to get parts) with a solenoid issue on the turbo charger. And, since my turbo hasn't been working and its still braking, my assumption is that the tranny is doing this. See if I can get some answers. I can tell you that with 3000 miles, I am already getting @22 mpg on the highway. I've got a tonneau cover on when I'm not towing. My Tahoe never got that kind of mileage. Other than the fact that General Motors is much more demanding of their suppliers than they are of themselves, I haven't had any issues with my other GM vehicles. So, I'm looking at this latest setback as an anomoly. I would be interested if anyone else had issues with their turbo on the Duramax diesel.