Dd advises you to go to page 3 or 4 of the postings and check out a posting by 79-w150 on the same subject, and the replies. Id use a good grade of silicone ignition grease to seal the ignition, run breather lines for the differentials, all that obvious stuff. One thing i have learned tho, trying to keep mud and water out of somewhere only retains it when it finds away in. Solution...leave things open so they drain. And, follow the "severe maintenence schedule" to the "t",meaning drain all fluids if you even suspect contamination, and keep things washed clean. Dirt contains millions of microorganisms that love to digest things like electrical wiring and vacumn hoses much less rot your body. Be sure and flush your frame rails and underbody good. Better yet compute the cost of owning a presure washer vs the car wash if you mud on a regular basis. Once the vehicle is clean then regrease and relube to drive mosture out.