Hello all E53 owners. I just wanted to let you know that I am impressed with the towing capabilities of the E53 platform. My gross weight pulling a 2015 Keystone 25 foot Bullet trailer and vehicle included was 10100 pounds. We started in Marysville Washington, which is 35 miles North of Seattle and traveled to Deadwood / Sturgis South Dakota. I had no desire to go to Sturgis but we needed Oil and supplies and Deadwood is mainly a tourist town. the only issue we had was going up Hwy 14 through the Bighorn Mountains.
https://en.wikipedia.org/wiki/U.S._Route_14_in_Wyoming
We had to stop because my transmission was getting so hot I could smell it. But me like a dumb ass had it in "D" most of the way. So after letting it cool and using manual modes to keep the converter locked up we made it. The highest point in the hwy is 9430 above sea level. That was a scary climb. ON the way home we faced a vicious headwind of at least 30 knots
slowing us down to 55 to 60 mph. My average speed as per GPS was between 60 to 65 MPH running at about 2800 RPM with an average fuel consumption of 10.5 MPG. All in all I am really impressed with the journey from Marysville, WA. to Deadwood, SD. then to the Oregon Coast back home to the greater Seattle area.
If anyone things that an E53 can't haul a 25 foot travel trailer. PM me! I'll tell you otherwise!
EDIT: She has a 4.4 with the factory tow package installed.