Here I am

1200 miles in a Duramax

Attention: TDR Forum Junkies
To the point: Click this link and check out the Front Page News story(ies) where we are tracking the introduction of the 2025 Ram HD trucks.

Thanks, TDR Staff

Increase milage in a Duramax?

Spanked a Red 350 crewcab!

After just taken a 1200 mile hunting trip in a new Duramax I have a few observations:



1- The SWB comes with around a 25-27 gallon fuel tank, while driving 85 mph and getting an whooping 12 mpg this meant we stopped a lot for gas, almost halve the range I would have.



2- Economy 12 mpg(80-85 mph) with no trailer, and what's worse we got in a snow storm and used a complete tank of fuel at about 50 to 60 mph and only got 17 mpg at this speed I believe we would all be in the twenties with no trailer and at this average speed.



3- My buddy has 36K miles on this truck already and the check engine light has come on 4 times, once on this trip. The Chev dealer treated us like dirt in North Dakota but that another story.



4- Seems not be a very solid truck, when you shut the tailgate or doors they don't feel as heavy duty as the Fords or Dodges.



5- The truck may claim high numbers but the engine seems to work harder that mine when tackling the hills (even when my was stock). The transmission has to shift more to maintain 80-85 mph when pulling hills. Mine truck will not shift out of OD on any interstate hill to maintain 85 mph without a trailer.



6- The Allison transmission did impress me going down hill. However, has any one tried to back down a long dirt road with one, it is very low geared. Best just to find a place to turn around.



7- This truck was a crew cab and it was more comfortable interior that my quad cab would be. I drove about 600 miles of this trip and I have to admit it was a comfortable ride, but so is my dad's STS Cadillac.



8- Ugly, it doesn't look like a HD truck it looks like that Avalanche thing.





Why don't they make a cool Isusu Badge for this truck. :)
 
Calm down

1-we stopped a lot for gas:confused: Don't you mean diesel?It was a diesel engine right?



I like to correct you youngn's when you say you put gas in it and your driving a diesel:D
 
jdecampo



The dealer in ND would not even read the code for us, but my friend later has told me it was just a maintaince item. We were driving 80-85 most the time, but I get 16-18 at those speeds. I do wonder if he might have some other problem. At 35k miles he should be broke-in?
 
My truck would get 12 at 80 and I have 4. 10 gears. There must be something wrong. You got to love dealers that won't give you the time of day.
 
hanover,

I would think something is wrong with his truck only getting 12mpg. I don't drive at 80-85mph so I can't say what the mileage would be but I drive at 65-70mph and get 21-23mpg. Do you know if he is running stock tires? I know if you are pushing 2100-2200rpm your fuel economy will be low. The check engine light has me wondering more too.
 
He does have larger tires, so we used gps readings and no trip computer. He was about 7% off on his speedo readings. I wonder if the tire size is not programed into his ECM could it account for the mpg via shift points etc?
 
hanover,

Shift points on the Allison are not effected by tire size not being programed in the PCM. Only the ABS braking system. I have put larger tires on mine and didn't reprogram then added Tru-Speed reprogrammer with no change. The Allison figures shifts on the fly off of its own sensors.
 
JakeGMCHD



I have called my buddy and let him know his mpg should be better. I don't know what he will do. By the way, is his truck light enought to put load range "C" tires on it? thats the new tire he put on it.



thanks
 
hanover



I wouldn't run "C" range tires on it. I don't know what size or brand he has. But you can find a lot of load range "D" tires in just about any size. This is just my 2 cents.
 
Originally posted by JakeGMCHD

hanover



I wouldn't run "C" range tires on it. I don't know what size or brand he has. But you can find a lot of load range "D" tires in just about any size. This is just my 2 cents.



I agree, I would never drop below a D range on a truck this size. I can't say for sure, but the "C" range tires will probably wear faster on truck that heavy also.
 
Originally posted by lmills

With a load range "C" I hope he doesn't plan to do any serious hauling.



They won't be doing any serious hauling, it's a Chevy/car. :D :-laf
 
Last edited:
Back
Top