larry barnhart wrote:
the Allison on our 2001 3500dually with the 8.1 liter did a great job of holding speed towing down mountains with our 35 ft alpenlite that was a combined weight of 22900 lbs. but engines and trailers need to be matched for best results. The 05 Duramax and the 2001 8.1 worked the same going down the cabbage patch on 84. retired rv'r chevman
The 2005 Duramax did not have a factory exhaust brake.
Compare that 05 Duramax or that 8.1 to a a modern diesel with a OEM exhaust brake and you will find there is a significant difference in slowing power going down the grade.