Originally Posted by emm-dee
Oops. Misread. But, it does look like the trailer can exceed the truck tow rating. It must be a power issue because the tow rating for a 3.92 geared truck with the hemi gas engine is over 10,000 pounds.
The tow ratings for the diesel are lower than the hemi on the exact same suspension because the intercooler on the diesel is in front of the radiator. Heat from the intercooler adds to the engine heat so on the worst case the ECM will reduce engine power to prevent overheating. In practice, if the trailer is under 7,000 pounds this is almost never a problem. You may have to slow down a little on big hills, but you'll be rewarded with 13-15 mpg while towing. YMMV