Be sure to walk around the truck and inspect all areas of undercarriage. If you notice any rust or unusual wear, it may something you need to address. Make sure you are also checking for any and all holes in the frame as well. Make sure all reinforcements or structures (example: running boards) are securely fastened to your truck so that they do not swing freely, then move up to where you can see into the engine compartment. You should be able to see clearly into this area and make sure there is no excessive dirt, grime, oil leaks or other fluids. Also check all hoses for leaks; if you find a leaky hose, replace it immediately!