The importance of WD-40 since you run your truck in wet conditions and clean it with a hose
After running a vehicle in the rain or through mud, snow and water it is highly recommended that it be cleaned. The reason is not simply to keep your vehicle looking good, but to prevent rust and corrosion. Rust and corrosion can cause parts such as bearings to wear out prematurely. Begin by removing the body and batteries then rinse the vehicle thoroughly with water from a garden hose. An old tooth brush may be needed to help remove some mud, but do NOT use a high-pressure nozzle or power washer. Once the vehicle has been rinsed thoroughly, if this hasn’t already been done, poke a few small holes along the seam in the middle of the tire. Turn the transmitter and vehicle on and spin the tires up to speed. The object is to get rid of as much water as possible that has accumulated inside the tire. Next, remove the wheels and spray the bearings with something such as WD-40. This helps to repel moisture and lubricate the bearings. Once done dry off the vehicle with an old towel as much as you can then let the vehicle air-dry. Once the vehicle is dry store it in a safe and dry environment.