Originally Posted by Black Sheep
Girlfriend had a 05 z71 with every bell and whistle. 3.42s are terrible and wanted to kick down at the slighlest grade running 80. Ive picked up a couple 2wds with 3.23s, worthless.
I had a 05 4x4 tahoe with 4.10s. Exact same mileage with 100x the performance. If i had to own a gm gasser, i wouldnt buy one without 4.10s, fuck anything else. Theres no advantage to the higher gears.
The whole 3.73 or 4.11's for towing is only relevant to the 4 speed trucks, for a 5.3 / 6 speed truck 3.42's are the deep towing gears...
For a occasional tower - mostly DD the 5.3 / 6 speed 6L80 combination is much, much nicer as the 4.03 first gear in the 6L80 will make the overall ratio with a 3.42 rear end deeper (13.8) than a 4L60 with a 3.06 first gear and 4.11 rear end (12.6) but still have a ~30% higher top ratio for unloaded use (2.28 for 6L80/3.42 vs 2.86 for the 4L60/4.11).
When towing there is not the annoying hunting between 3rd and 4th that the 4L60 does plus you can lock out 6th, 5th & 6th, 4th, 5th & 6th etc. with the 6L80.
5.3 / 6L80 trucks with the tow package will come with a tranny cooler and engine oil cooler as part of the package and a trans temp gauge is part of the information display.
And when I went from pretty much the same truck in 4.8 / 4 speed / 3.73's to 5.3 / 6 speed / 3.42's with the AFM my mileage went up 2-3 mpg.