3.42 (tow package) rear end

[Steve1081]

It isn't that far off from the base 3.08; but in all the reviews I have read online I have not seen anything about the effect of the 3.42 on mileage or performance.

I'm wondering because I'm still debating the SLT with tow package vs Denali. The price difference the way I want it equipped (basically no options on the denali and only buckets, nav, 20s and tow on the SLT) is roughly $5k.


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[Steve1081]

Anyone with the 3.42 rear in a 5.3 truck that can comment on mileage?


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[BirchyBoy]

Have you compared the EPA mileage ratings for the two models? You'll likely get lots of varied stories on MPG, but they are all relative to how a person drives. At least the EPA ratings should use the same methodology.

 

[jmitchell]

I've got the 3.43 with the tow package on my '15 but I only have 300 miles on the vehicle right now. I am still in the break-in period so I haven't gone over 65mph at all yet (been hard to stay under 55mph per the book). Mostly city driving and a couple of 30 mile highway trips. I am getting 16.5mpg right now and have yet to finish my first tank of gas.

As a comparison, my '07 had the 5.3L as well but not the 3.42 rear end and I never reset the mpg meter for the life of the vehicle. At 120,000 miles I was at 15.8mpg for the total life of the vehicle.

 

[BRUTUS_T_HOG]

I get 17-20MPG at 70mph unloaded. Towing light loads I get about 14-16mpg. Using the instant economy feature. 17-18 avg.

Have used chevron or shell fuel for the last 2 years and 30k miles. Running 5w30 synthetic oil. The tires are the factory size and running the recommended 35psi.

 

[Steve1081]

EPA is the same... But, I am guessing it will be a tad worse with the 3.42 at higher highway speed 70-75; just due to slightly higher RPMs. Buying a truck with the tow package tomorrow. So, I will follow up on this in a few weeks.