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Old 10-15-2011, 11:00 AM   #1
dmarty
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Join Date: Dec 2008
Location: Verona, WI
Posts: 97
Which axle 3.08 or 3.42?

Hey Guys. I’m spec’n out a new 2012, 5.3 LTZ 4WD to replace my ’99 and want to know what axle ratio to get. Dealer says 3.08 is standard, but I’m think’n that’s gona be too doggy, but maybe I’m wrong. He says most people get a 3.42. That’s what I thought I had in my ’99 5.3 4WD 4L60E, but I found my window sticker and it says I have a 3.73 which I really like. Tire diameters are the same ‘99 vs. ’12 (different wheel size, but overall diameters are same) and ratios of the 6L80E in the ‘12 are 4.03, 2.36, 1.53, 1.15, 0.85, 0.67 and the 4L60E in the ’99 are 3.059, 1.625, 1.00, 0.07 so it looks like the ‘12 will have a slightly higher gear ratio (lower numerically) in OD, but much lower in first than the ’99 so I’m thinking that I might go with the 3.42 as the 3.73 will be way too low in first. I’m an old guy and like a little performance, but still want decent mileage as I drive about 30k per year. The truck is lightly loaded at about 200-300 lb plus driver most of the time. I have a small utility trailer that I take to the lumber yard a few times a year, but never pull a boat or RV trailer and all of my driving is in the Midwest on freeways with no mountain roads. So what do you think is the best ratio for me 3.08 or 3.42? Thanks!
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99 Silverado 1500 LT with 315K miles
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2012 GMC Sierra SLT
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