Differential Gear Recommendations

[rngr746]

I condidering a purchase of a 2012 1/2 ton Sierra with the 5.3L. My driving is 90-95% rural county roads ranging from level to gently rolling and 10-5% highway driving. I do not do any towing and occasionally haul a load of firewood. The differential gearings available are 3.23, 3.08, 3.73, 3.42. I'm interested in members opinions on which would give me the best mpg's.

[travis73]

Well with a 5.3l 4x4 you only have 2 options 3.08 or 3.42,I would recomend 3.42,there has been a lot of discussions on here about which is better and I believe the general consensus was the 3.42 was the best option.My truck came with 3.42 ratio and I am verry happy with it with the 6spd.

[Big Whiskey]

Yep, I'd go with the 3:42

[chakis24]

3.42s. the 3.08s is how they get the high highway mpg, and since you wont be doing much highway they wont help you. if anything they might hurt because it'll be a dog off the line.

[rt66er]

I'm gonna buck the trend here and say 3.73. It sounds like you do the same type of driving I do, and with the 3.42 gear (what my 11 Sierra has), it spends too much time bogging down at less than 1,500 rpm. With a little more rpm, I believe the AFM would be in use more consistantly and would achieve better mileage. Plus, you get better acceleration when you want it. Best thing to do is spend a bit of time test driving in the exact conditions you expect to encounter and see how you like it.