I suggest you list the make and model of your vehicle including the engine size, horsepower and final drive gear ratio. By doing this you'll get some real-time info.
Just as a reference, many years ago I had a class C built on a Ford E350 chassis with a 460 CID engine. I had a 4.10 final drive. I pulled a 7,000 lb enclosed trailer with relative ease. Yes, it slowed down on steep hills but that was to be expected.
2016 Newmar Dutch Star 4369
Newmar Owners Club
USAF 1966-1969,- Law Enforcement 1969 - 2003, Retired since March 2003