First TT - Of course plenty of questions!

afidel wrote:
Not that I disagree with the majority of your statement, but the 1st and 2nd final gear ratios with the 3.42 and the 6 speed are actually about the same for towing compared to the 4.10 with the 4 speed so the need for anything over the 3.73 is basically nill (2.48 vs 4.03 1st gear is huge).

For overall use the newer 6-spd which I have in my current 2012 Silvy is certainly an improvement over the previous wide ratio 4-spd I had in my previous '05 Avalanche and '06 Silverado, ALL with a non-tow friendly 3.42 axle ratio, same 5.3L engine, 'though my current '12 does offer a bit more grunt than previous incarnations. Regardless, I'm not towing in 1st or 2nd - with the 4-spd I always towed in 3rd, Tow/Haul engaged with the engine spinning ~ 2300 rpm at highway speeds, with my current 6-spd I tow in 5th, Tow/Haul engaged with the engine spinning ~ 2000 rpm. That's no so good actually, as it doesn't take much of an upgrade or much head wind to force the transmission to downshift to 4th whereas with the previous 4-spd I merely continued on in 3rd, no downshifting at all. Had I purchased this '12 as a new vehicle I'd have insisted on a 3.73 axle ratio driving 18" tires but since I bought this truck used I'm stuck with it's 3.42 axle ratio driving 20" tires, both of which contribute while towing to excessive downshifting to 4th anytime road conditions are less than ideal. Bottom line - there's more to the story than just saying the newer 6-spd makes up for a less than ideal towing axle ratio, which in the GM world starts with a 3.73. Run a 3.42 or 3.23 or 3.05, even with 18" tires, and a GM 5.3L 1/2 ton WILL suffer the consequences when towing regardless that it may be running the newer 6-spd.