I have a '95 3.0l with auto trans, 3.45 gears. New head gaskets, full tune up, etc.. I get 21-22 at best. 19 has been my lowest recorded. However, I haven't done any real highway driving and checking the milage afterwards. If more hwy driving I would expect it to be a couple mpg higher.

For the poster towards the end of the 1st page who said they did 99% hwy driving and have 4.10 gears. I would DEFINITELY switch to something like 3.45s.. I think thats where people will notice the biggest difference. If you want better milage, and do mostly hwy driving, I'd switch out anything over 3.73s for something lower. You'll lose alot of quickness off the line, but your mpg will improve a ton on the hwy. It's also much easier on the motor (will run at lower RPMs).

I'm temped to switch my 3.45s for 3.27s or 2.73s..but the truck is already so slow.. I can't really make it any slower off the line and still be safe to drive in town lol

I may look into an underdrive crank pulley.. I wish I had explored that back when I had the motor out of the truck and did the timing cover/water pump seals.. That would have been the perfect chance to swap that.. If it makes a 2mpg difference and is around $50, Id say it would definitely be worth doing.


Most people think I'm doing good with a truck getting 20+mpg, but I'm used to always having cars that got close to 30mpg..So the switch hurts a little. I try not to make unnecessary trips. I can't understand why or how anyone could be driving these real big trucks and SUVs getting like 15mpg or less. To me that's just crazy.