HWY 139 Colorado

Just arrived in Grand Junction, from Vernal, Utah, through Rangely and Douglas Pass on Hwy 139. The grade is 7% both sides of the pass. I am towing a 34 ft Big Country 5th Wheel behind a Chevrolet 2500HD, 6.6 Duramax Diesel/Allison Transmission. First, the speed limit over Douglas Pass does NOT exceed 25 MPH and for short distance is down to 15 MPH. The road is narrow two lane, twisty, but on most switch backs there is additional lane width. I drove the highway at the limit, in 3rd gear, difficult to keep the speed down to 25 on the pull up the hill. From the summit, elevation 8268, south I left the trasmission in 3rd gear and used the brakes a little. We had no problem with over heating, either the engine or the brakes. We cut about 100 miles off the distance to Grand Junction by using 139 thru Douglas Pass. The last 6 or 7 miles, approaching I-70, is a little rough road.