Gears and MPG
 

so now that lockers are hitting the market I'm going to be picking up one for my truck and I think I want to change gear ratios also while I'm at it...

I've heard of people going to 3.90 and 4.10s with the 6L80E and actually not hurting MPG...

If that's true I'd love to go to at least a 3.90 gear (have 3.42 now) what do you guys think, does the 6spd not lose as much mpg as the 4L60E did with a lower rear gear?

In for responses. What tire are you running now? I'm 3.5" shorter than factory and that was a bump of about 250 rpm @ 70mph

I feel like this may hold water, mine seems to like to get better economy at 80 then 70, I think 3.73 or 3.90 would be good in mine vs the 3.42.

I forget the OD ratios.

Mine seems to be the same, 60-65 not so good, 70+ much better

4L60e - .70-1
6L80E - .67-1

Pretty close

Mine with 33" mud terrains does better around 60-65 than 50-55 also. 3.42 rear end as well.

Not apples to apples but my 99 with 3.90s and .7 od got every bit as good as with the 3.42s and was WAY quicker. My 14 averaged exactly 20mpg driving 80-85 from Austin. It got exactly 21 going to Austin driving 75-80. Slower than 70-75 doesn't do as good. I think gears would be a good move.

Swapping 3.42s to 3.90s my 2000 picked up fuel mileage in every area. Keeping in mind that I have a 60e and 31.9" tires.

well it appears that 3.90s aren't an option 3.73 and 4.10 is all I've been able to find... what do you guys think, all around best bang for the buck (same price lol) best performance gain vs. least mileage drop (or possible gain)

I'm wanting 3.90 as well but may just go with 4.10. Which brand gears and locker are you looking into?