My 2001 duramax with edge tunner on the economy setting would get 20-22 mpg around town. But with the edge tunner you realize why th fu ck did I buy this thing for anyway. So it stayed in level 5 forever. But still got 16ish without romping on it and rolling coal on those hybrid vaginas. Keep in mind I have smoked mustangs from light to light with a 10 k lb truck. But I'm still pissed off that my new truck( yet only 3k miles on it) best mpg is 17. She hasn't been doing much other Han towing the boat or my machines. But I did reset the gauge after my horrible 6.8 mpg .

yes !!!!

My 2015 HD gets 20 mpg at 75 mph highway- not towing. It gets 14 towing my work trailer at 70- which is square and tall with the aerodynamics of a brick. If I tow it at 60 mph I get 16 mpg.

My 03 DMax was the best of the ones I have had. Did intake and exhaust, Bully Dog programmer, got 19mpg all day and 13-14 towing. Best part was the power, at max tune it would break the 33's loose at 30 on dry pavement. The upgrades did more on that truck than I could believe, was like a second engine under the hood.

I have had 4 of them, a 02, 04, 06 and my current 08, all Crew cab, short box 4x4's. My 04 even though it was identical to my 02 got best mileage, saw 19.5 empty running fast on highway from fla to mi turned up 90 hp over stock, it would regularly get 17-18 empty on highway at 80, 13.5 to 15 towing my 272 at 80 mph, 12.5 towing 3000 lb snowmobile trailer in winter. I run highway tires on all of them in summer and skinny snow tires in the winter, the guys with big tires look like tards in a snow storm going 45mph in 4x4 with white knuckles. My current 08 is absolutely the worst mileage out of all of them, with dpf delete, tune,it gets 10.5-12 towing my 272, 9.5 to 10 towing the new 33 scarab , 9.5 to 10.5 towing 3000 lb snowmobile trailer and 14.5 to 15 empty. Now IF I baby it on a 2 lane highway at 58 mph I could get trip computer to show 20.5 to 21 for 100 miles after resetting it but the minute you crack the throttle that drops off face of the earth. Tried every version of the tunes from econo to 150 hp, seems to get BETTER overall mileage at 70 or 90 than 50 or econo.
We rebuilt a transmission on a 04 or 05 dodge dually extended can 4wd six speed stick, had highway tires on it, no mods, I put 100+ miles on it breaking new parts in and I was in disbelief that it got 20+ mpg at 65-70 mph, too bad they ride like crap and fall apart!

Smart man. Amazes me how many people don't get this even up here! Big tires = flotation !

I was shopping for the 06-07 classic Silverado for the updated front end and 6 speed transmission but I got a good deal on my truck and it's really clean/good shape.

I'm running 2k RPMs going 70-75mph. How does the 6speed compare? Does it shift a lot between 55-65mph?

That will probably be my next truck. Crew 07 classic. I like the older preadmission trucks. Love that body style. Cash deal, lower insurance, cheaper to licenses, reliable truck is what shoot for.

Some of these guys are going by the lyometer thats a no no .

Np

Yup I used to run tall skinnies in the winter when I did a lot of trips north snowmobiling. Friends used to make fun of the "pizza cutters" but they were 1000% better on winter roads and would go through an amazing amount of fluffy lake effect snow.