Quote:
Originally Posted by cosmick
The 3.23s are too tall for best mpg, but they do let you shift to a lower gear at higher speeds, which can help highway towing.
When it was new, and came with 3.42s standard, GM called the 4.8 " a real sweetheart " in regard to fuel efficiency, ( stock ).
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Per the owner's manual, for my Tahoe (2005) 3.42 gears aren't actually offered. They were standard on 4wd and 2wd 5.3L Suburbans could get it, but 2WD Tahoes only got 3.23 or 3.73. Mine is RPO code GU5, so I have the 3.23s
I've had tank averages in our Tahoe at 23-25mpg... but only on long highway trips. This is just setting the cruise control and letting it go down the freeway.
On my old Silverado, I had a handful of tank averages at 20-22mpg, commuting in mixed traffic. I could have done so more often, but I rarely went a whole tank w/o heavy loads/towing, especially considering a tank could get me nearly 700miles.
Again, for belly pan ideas, check the Silverado thread in my signature. I have a few pictures in there of how I built the framework it mounts to. Coroplast worked well and even had some hard impacts with road debris and was left mostly unscathed. It's pretty durable, but inexpensive and lightweight.