The Klever RTs in 10.5 are the same load range as what came factory equipped on your PW. Tire shops aren't the automotive engineers who designed the Power Wagon. For 3/4 ton trucks a Load Range E is usually the choice, but for the Power Wagon it came equipped with D's.
35x10.50R17 Kenda Klever R/T KR601 121R D/8 Ply BSW Tire
BTW, my tire shop manager came out of the shop and informed me that 3/4 ton trucks required 80 PSI in my Load Range E tires after I asked the installer to fill my once new Toyo 35's to 42 PSI. I quickly noticed after leaving the tire shop that the maximum PSI stated on the tires is 65 PSI. Glad that I didn't go straight onto our 75 MPH highway, but spent the time to deflate.