real life MPG differences (3.08 vs 3.42)

[RST Dana]

While I agree, would you specifically be able to tell? Your 3:42 is a 2015+ which also has more power.

3:42 is a must. But after about 75mph it’s running higher rpms than I’m use to because almost everything else I’ve driven in the last 4 years has had 8 gears. Whish the 5.3 would’ve got the 10 speed too. I’m sure it’ll trickle down eventually.

I agree I love the extra HP, having the 3.42 is almost as good as having 4.11 with my Big Blocks in the 60's!

 

[Vimes]

You ought to try it with 4.11s then. Put them in my 2015 with a speed, and it flies down low. Runs out up top though, as expected. Lost about 1.5mpg over the 3.08s. If I had it to do again, would go with 3.73s, I think. It drove like a school bus before, runs more like a car now.

 

[GTNator]

Around one mpg better on the 3.08. We have two trucks, one with and without the tow package.

Do you notice a "power" difference between the two?

 

[swathdiver]

Is that mileage while towing?

I'm running a 15 burb with the towing package and regularly do 21-23 highway mileage. In running Michelin at2's 38psi

Not towing anything

How are these tires wearing at 38 psi? Which size are you running?

 

[Blueinterceptor]

Tires look like new. 275/55/r20
Standard pressure is 35 psi. I’m not really that high

 

[sam123]

Do you notice a "power" difference between the two?

Yes. The suburban has the 3.08 and feels slower than the Yukon that has a 3.42. In my experience though, the 3.08 gets better MPG especially on the highway