I have a 1990 motorhome with a 454 4bbl. I am currently using rotella 15w40. I plan on going cross country to Oregon next summer and thought a thinner oil might help out on gas milage. Also thought about synthetic but afraid of possible oil consumption. The motothome has 18000 miles on it. (original). Any thoughts? And what about synthetic trans fluid? ![[Confused]](images/icons/confused.gif)
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