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Lower Gears Higher Highway Mpg?

TheGreekIndian

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TheGreekIndian Enthusiast

TheGreekIndian

Posted
Posted

Going to buy a 2011 Silverado and was curious what gearing is better for highway MPG for 5.3L? 3.42 or 3.08? I may never tow anything, so that is not an issue. I heard 3.08 gear would yield slightly higher MPG...

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powerhaulic Enthusiast

powerhaulic

Posted
Posted

Wish the 3.73 was still an option w/5.3

 

Get all the gear you can.

 

IMHO unless there are NO hills or mountains any where that you drive, you will not see better mileage with a numerically lower ratio

stlavsa Senior Enthusiast

stlavsa

Posted
Posted
Wish the 3.73 was still an option w/5.3

 

Get all the gear you can.

 

IMHO unless there are NO hills or mountains any where that you drive, you will not see better mileage with a numerically lower ratio

'

Get the 3.42

oldmann Senior Enthusiast

oldmann

Posted
Posted
Lower gearing would mean lower RPM's at speed, so yes, you would get slightly higher MPG's. Personally though, I would still go with the 3.42 gearing.

 

 

Hmm. Here we call a 4:10 a low gear and 3:08 is a high gear. No tow.. go with the 3:08. The six speeed makes up for the rear gear being so high. JMHO :rolleyes:

Stevens03 Senior Enthusiast

Stevens03

Posted
Posted

There was a big conversation about this recently :rolleyes: I believe we decided the 3.42s were the best choice for mileage. :sigh: "Most" agreed the 3.08's left the truck feeling underpowered.

Stevens03 Senior Enthusiast

Stevens03

Posted
Posted

Search the thread about Tuned 4-speed verses stock 6-speed. Good reading for sure and lots of opinions.

Zed-Seventy-One Enthusiast

Zed-Seventy-One

Posted
Posted
Lower gearing would mean lower RPM's at speed, so yes, you would get slightly higher MPG's. Personally though, I would still go with the 3.42 gearing.

 

 

Hmm. Here we call a 4:10 a low gear and 3:08 is a high gear. No tow.. go with the 3:08. The six speeed makes up for the rear gear being so high. JMHO :sigh:

 

 

I should pay more attention in my posts... :rolleyes:

 

Higher gearing is what I meant :lol:

Zembonez Senior Enthusiast

Zembonez

Posted
Posted

Don't do this for better mileage! I went from 3.23s to 3.73s and mileage stayed almost exactly the same.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted
Don't do this for better mileage! I went from 3.23s to 3.73s and mileage stayed almost exactly the same.

 

Tends to be what you lose on the highway mileage you gain back in city mileage. Stick to the speed limit and highway mileage will not suffer

johnnyz71 Enthusiast

johnnyz71

Posted
Posted

I don't understand why everyone is stating that the 3.08 is leaving the truck underpowered. I think you guys are putting a little too much on the 3.42 ratio. With the 6-speed tranny, the 3.08 is like the 3.73 with the 4-speed, that has been stated by many people. Even if you tow, the 3.08 can still pull trailers. I see no problems with the 3.08, my truck gets up and goes!

powerhaulic Enthusiast

powerhaulic

Posted
Posted
I don't understand why everyone is stating that the 3.08 is leaving the truck underpowered. I think you guys are putting a little too much on the 3.42 ratio. With the 6-speed tranny, the 3.08 is like the 3.73 with the 4-speed, that has been stated by many people. Even if you tow, the 3.08 can still pull trailers. I see no problems with the 3.08, my truck gets up and goes!

 

Yes the truck will "get up and go" thats where the six speed comes in. Makes the vehicle accelerate very well with a numerically low ratio (ie 3.08)

 

Top gear performance without forcing a downshift is where the numerically higher ratio will improve performance and in many cases improve fuel mileage. ie. 3.42 or even better 3.73

 

The overdrive ratios we have in modern transmissions put the cruise RPM too low and out of the torque peak when combined with 3.08 ratio. Get those RPM's up and improve mileage without excessive downshifting

Prokopchuk_9 Senior Enthusiast

Prokopchuk_9

Posted
Posted
Lower gearing would mean lower RPM's at speed, so yes, you would get slightly higher MPG's. Personally though, I would still go with the 3.42 gearing.

 

 

Hmm. Here we call a 4:10 a low gear and 3:08 is a high gear. No tow.. go with the 3:08. The six speeed makes up for the rear gear being so high. JMHO :rolleyes:

 

 

thats the way it is...i deal with gearing, and making gears all the time gotta remember ur driver vs driven...lower the first number in the ratio, the less the pinion has to spin to turn the ring once, giving you a higher ring speed. just like any other. the rear end of a car is just about on the same principle as almost any other bevel gear. the only thing that differs with hypoid gears is that the pinion is offset to the center of the ring. the lower the first number in the ratio the higher its geared. higher=lower gearing

 

long story short, 3:08 is pretty high...ive heard guys with it and they shift all the time. for the amount its gonna save you in gas vs. 3:42 is it really worth all the annoying shifts every little lump on the road????

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