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Username Post: 2017 Duramax fuel mileage        (Topic#348466)
Forum Newbie
Posts: 1

Reg: 11-29-17
11-29-17 05:39 PM - Post#2716307    

I have a 2017 2500HD Duramax that has 12,000 miles. I have been averaging around 20+ miles per gallon Diesel at 70 miles per hour but when I connected my recently purchased 42ft 5th wheel (12,000 gvw) I found my mileage dropped to around 9 mpg at the same speed. Is this normal? Has anyone else experienced this? I find it kinda hard to believe that I would lose over 1/2 of my mpg by towing my trailer.
Other than this anomoly, I love my truck!

Dedicated Member
Posts: 5341
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
11-30-17 05:00 AM - Post#2716358    
    In response to JoeVet

Yes. Mileage will drop drastically pulling a 42 ft trailer or any trailer for that matter. It weighs more than the truck +++ the aerodynamic drag.

My 2015 6.2L drops to 10 from 21 when towing just a 14 ft enclosed aluminum with my RZR.

2017 GMC Sierra Denali Ultimate 6.2L(420hp)/8-sp Z95
2016 Polaris RZR 900 EPS

"9th Year" Gold Supporting Member
Posts: 1838
Age: 68
Loc: south texas
Reg: 08-04-12
11-30-17 09:03 AM - Post#2716381    
    In response to JoeVet

It's really weird how much most diesel pickups' mileage drops with a trailer. I bought a 2007 GMC Sierra Classic new. Old body style because it has the 8.1 gas engine. (the diesel engine increased the price by $10,000)
As a little side note. My truck is the last big block that was put into a pickup at the factory. Literally the last one. I had to travel 1400 miles to get it.
It gets 9 mpg running 75. Hook it up to my 36' camper, and it only drops to 7.5. Go figure.


if you're gonna be a bear...................

if you're gonna be a bear..................

1960 Biscayne (the 6T)
2005 Yukon XL
2007 GMC Sierra Classic 8.1
2009 Silverado
2011 Escalade ESV

Silver Supporting Member
Posts: 50
Loc: Portland, OR
Reg: 04-16-13
01-13-18 01:56 PM - Post#2720951    
    In response to JoeVet

I have a 2015 Silverado 1500, 5.3, 6 speed auto, 3.42 axle. 4wd
22 mpg @60 mph level hwy
15-16 mpg @ 60 mph towing a 6000 lb open car tlr. on level hwy
10-12 mpg towing over mountain passes


Senior Member
Posts: 1067
Loc: Buffalo, NY
Reg: 06-13-06
05-04-18 08:02 AM - Post#2733031    
    In response to beagrizzly

A side note to your side note, I hear they are retooling up the Tonawanda engine plant nearby me to bring back the big block!

'56 Chevy 4dr 210 327ci
'97 GMC K1500 Suburban 6.5TD

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