I have been maintaining a fleet of approximately 55 light, medium and heavy vehicles for over 20 years. Most are 4X4 pickups and off road fire fighting trucks. Some medium duty trucks. Some military light trucks. I can answer most questions concerning 4X4 engine, drive line, suspension, electrical, and fuel, both diesel and gasoline. Ford, GM, and Dodge, old and new, but prefferably not newer than 99.