MPG difference between 3.08 and 3.42 ratios

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,104
Reaction score
25,039
Location
Treasure Coast, Florida
I get 15 around town and 24 on highway on my 18 Tahoe 5.3 4x4 3.42 rear AFM off running Diablew 91/93 tune. Transmission and differentials filled with AMSOIL Signature. Don’t know if that makes a difference. Very happy


Sent from my iPhone using Tapatalk

I reckon those Amsoil products are worth at least 1 mpg Robert, great stuff!
 

Bob2C

Full Access Member
Joined
Jun 11, 2019
Posts
532
Reaction score
430
Location
Northern VA
I reckon those Amsoil products are worth at least 1 mpg Robert, great stuff!
I think so. I am also running AMSOIL xl in the engine for the first time. I think I would be waisting the signature changing it out at 6k mike intervals. I still run the ac Delco PF63e. I’m happy


Sent from my iPhone using Tapatalk
 

exp500

Full Access Member
Joined
May 14, 2017
Posts
1,781
Reaction score
1,609
Alot of discussion on gears no matter which section of forums you are in..... Mileage, performance, towing, Offroad. Simple explanation is 308/342/373/410/455 - each step is about as close to 10 percent as you can get- So any changes one step will be minimal, about the same as 2 different drivers. Takes a 2 step jump to be significant. So in the end it comes down to how you drive. Over 80 need 373 or less(engine RPM). Always remember, the faster you spin driveshaft, the more relible the driveline is (less stressed).
 

59yukon01

Full Access Member
Joined
Jun 14, 2019
Posts
154
Reaction score
600
Have a 2016 Yukon with the 3.42. Last trip from KY to FL and back I averaged 20-21 on the hwy, but that was at pretty much a constant 80 MPH.
 

stallion_412

TYF Newbie
Joined
Jul 31, 2020
Posts
13
Reaction score
8
Location
IA
2015 Yukon 4x4 5.3l engine w/ 3.42 rear end. Average 23-24mpg at 75mph.

What really surprised me is how much better it is than my pickup which has the same powertrain. My pickup only gets ~19-21mpg at 75mph, depending on a lot of conditions.
 

BMPNUGLS

Full Access Member
Joined
Apr 5, 2015
Posts
211
Reaction score
87
Location
Mid-MO
B6D3CDF2-6E64-4297-9868-2A015237A274.jpeg I have a 2016 Yukon XL Denali (4wd) with 6.2L and 3:42’s. Range AFM Disabler always plugged in. It’s got 95K miles (regional account manager so lots of windshield time)...on average I get 23/24 Hwy and 15/16 in town. BUT I have also done a couple long trips with cruise set at 65mph and got 28mpg!
I do keep all maintenance up religiously, have a AEM dry flow air filter, clean the MAF sensor & air filter every couple months, and run a personal concoction mix of fuel system cleaners at least once a month with a fill up. Not sure if any of that matters but thought I’d mention it.

I should also add that I always (for the most part) use 93 octane fuel or at least 91....preferably Shell or BP.

To this day I’m still amazed at the mileage I get with the 6.2 and brag about it every opportunity I get! Lol
 
Last edited:

RST Dana

Supporting Member
Joined
Jan 15, 2018
Posts
1,469
Reaction score
1,195
Location
OH
View attachment 254795 I have a 2016 Yukon XL Denali (4wd) with 6.2L and 3:42’s. Range AFM Disabler always plugged in. It’s got 95K miles (regional account manager so lots of windshield time)...on average I get 23/24 Hwy and 15/16 in town. BUT I have also done a couple long trips with cruise set at 65mph and got 28mpg!
I do keep all maintenance up religiously, have a AEM dry flow air filter, clean the MAF sensor & air filter every couple months, and run a personal concoction mix of fuel system cleaners at least once a month with a fill up. Not sure if any of that matters but thought I’d mention it.

I should also add that I always (for the most part) use 93 octane fuel or at least 91....preferably Shell or BP.

To this day I’m still amazed at the mileage I get with the 6.2 and brag about it every opportunity I get! Lol
What’s that song?
I can’t drive 65!

me either, that’s why I average 20-23 at 80.
 

BMPNUGLS

Full Access Member
Joined
Apr 5, 2015
Posts
211
Reaction score
87
Location
Mid-MO
What’s that song?
I can’t drive 65!

me either, that’s why I average 20-23 at 80.

Ya the drive to one of my accounts is mostly 2 lane country road all the way there...w troopers everywhere along the route...lol. But I’ll still get 22+ running 80+ on I-70 usually
 
Top