I have done 4 loads of gravel in my Ram 2500 that were each in excess of 7000 pounds. It is only rated for 3600lbs payload but the move was in town from burnco to forest lawn. About 7km one way and it didnt hurt the truck one bit. I saved the recipt because i know there will be a few non belivers. As long as it isnt resting on the bump stops i dont worry. The closser to the cab the load is the more you will be able to excede payload.
Disclaimer i know this is really hard on the axles and arguably unsafe.
Disclaimer i know this is really hard on the axles and arguably unsafe.