4L60E and 4L80E are automatic transmissions. Using a 4.10 gear ratio in the axles has nothing to do with the transmissioin.
If you are getting 12 mpg in the city, then something isn't right. I would think even with high gearing your truck should do alot better then that. But lower gears usually allow better MPGs in the city and a little worse on the highway and interstates. But that isn't always true. Its very possible to get better MPG on the highway with lower gears, especially if the road goes over mountains.
If you are getting 12 mpg in the city, then something isn't right. I would think even with high gearing your truck should do alot better then that. But lower gears usually allow better MPGs in the city and a little worse on the highway and interstates. But that isn't always true. Its very possible to get better MPG on the highway with lower gears, especially if the road goes over mountains.