I forgot bout this thread.....my 01 QCLB cummins 6sp with 4:10's only mod's are quadzilla pluse v2 straight pipe and a BHAF i get 18 average and i drive it like i stole it all the time lol it dont ever get a break

My OBC says.......Your gas mileage sucks, have fun filling up.....

My 08 qc 4.7 4wd 6 inch lift on 20s wrapped in 35s 3:92 gears got 9 in town and 12 ish on highway

3:92 is low geard for a gas truck.....my 4:10's are retarded low
This 6th gear
http://i1129.photobucket.com/albums/...9/IMAG0172.jpg

I have 4.10s in my rt

We also have taller tires and more rpms I need 4.56s in mine something terrible

And much lower geared overdrive transmissions. My 6 speed auto in the Wagon has a 0.625 6th gear. Even with 4.56 gears and 34" tires, I'm running a hair under 2000 rpm at 70mph.

And MPG sucks, I get about 9-10 in town (with my heavy foot), anywhere from 12-15 highway depending on wind speed and direction, and 9-10 towing my boat, which is about 4k lbs after everything else is loaded up.

My tires are 32.2 in tall and I run around 2200 at 75

Im guna swap for some 3:55s cuz i can only turn 3200 rpm and make enormus amounts of torque between 1800 & 2200 rpm 4:10s r useless in a cummins......i can bearly squese 100 mph out of her but she will get from 0-100 dam quick if i stand on it i can be doin 95 at the top of a on ramp easy and still get 18 mpg