dmatt wrote:
What gear ratio do you have on the Durango? Is it a factory tow package? That will make a big difference on how it goes. Years ago I towed a 18' 1600lb boat with a V-8 Durango and it really struggled on any hill. It was my first time towing anything and I didn't know anything about towing. All I knew was it had a good tow rating and was a V8 so it had to tow the boat alright! Well, I was seriously mistaken. Come to find out, it only had a 3:08 ratio geared for highway miles. After towing in the Sierras I Burned up the tyranny! Expensive lesson learned.
All 2015+ year V8 Durango models have a 3.09 ratio, regardless of tow package. However, that doesn’t sound like your problem, since that ratio should be fine for towing. You didn’t say which model you had, but without the factory tow package you were possibly missing other internal components necessary for towing, including HD cooling. Many people have been tricked by unscrupulous dealerships. OTOH the R/T model without tow package (which I have), is only missing a wiring harness and hitch receiver. Also I’ve read that earlier models had a tow mode that you had to manually enable, whereas newer models figure it out dynamically depending on load. I don’t know if that affects gear mappings, but I suspect that not enabling towing mode in a pre-2015 Durango would have been a problem.