Towing Jeep with Mercedes 3500 BluTec Deisel

My 3500 is a Pleasureway Plateau TS with a hitch rating of 7,500lbs but I guess if the GVCWR is 15,000 lbs then my max toad would have to be 15,000 minus my fully loaded RV with liquids and passengers with cargo, ??11,000?? and as you point out that leaves @ 4,000 lbs to pull. I should tow 4,000 max. curb weight then.

Thanks.