I have a couple issues that maybe some of you could shed some light on.

First, on a trip this past weekend I did my first tow. The truck ran great! Once up in the higher elevations, we started noticing a strong propane type smell in the cab. The windows were open. It was so strong I pulled over and checked my trailer for leaks. It wasn't the trailer. Once camped, the smell came back while driving solo so it has to be the truck. Any ideas? odo was about 850 miles.

Second, there is a clunk or hard upshift I think from 2-1 shift. It is in either normal or tow/haul. Thanks.

 

You're getting exhaust fumes in the cab; new diesel emissions smell like propane. Try rolling the windows up.