In July i went up the Green River Gorge on I-26 in North Carolina it's a 7% Grade. Coming from South Carolina. I was doing 3000 RPM at 40 MPH in the right side truck lane. My truck is a 2002 Dodge Ram...
Sounds like the 99' 3/4 ton Dodge I had in 2005, but mine was a 3 speed w/ an OD. I pulled about the same trailer then too. Always made me nervous to be way out of town an that engine screaming up hills. Sold it to go with an 01' Dodge with a diesel & a 6 speed manual. Much less stress on me, and the truck.