Before you look elsewhere, be sure the motor mounts are in good shape. Chock the rear wheels tightly ahead and behind both wheels, and try to move the truck forward and back while someone watches the movement of the engine. There should not be a great deal of movement. If the engine shakes violently or has a lot of motion side to side as the load goes on, look for broken or deteriorated motor mounts. If it's chocked properly, the truck won't move, so don't expect to jump the chocks.
Jerry
