I've started reading about Synthetic Oils.Found a web site for Amsoil(NO, I'm NOT a dealer,salesman,or whatever)I'd like to start using their motor oil in my F-150(90,000 miles and still makin' payments)gas engine. I try to do as much research as possible on a new subject and was curious if anyone on this site has used any synthetic oils( motor oil,gear oil,transmissian oil, etc)in their trucks or personall vehicals. If I'm on the wrong site to ask this question, I'm sure someone will steer me in the right direction. Thanks....