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...
On my '04 Chevy 2500 (4 speed), I'd frequently hit 5000-5200 on some really steep hills when pulling the FW. Even then, I'd sometimes get down to around 38-40mph on the 8% grades.