2021 Denali DMax, 5k mile driving review comparing with ecoDiesel

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steiny93

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Wife's Denali DMax is at 5k miles, figured I'd drop quick review post.
For some context, her truck sits next to a Ram 1500 ecoDiesel which shares its parking spot with a 6.7 cummins, so we are diesel heavy. However this is her first diesel, she has been driving denali's / tahoe's / escalade's / x5's.
1/3 of these miles are in town miles, rest are from a 1k mile trip and a 3k mile trip, this the xl with larger BF AT Ko2's for tires which hamper mileage a bit

Cons
- Uses a lot of DEF; appears to be about twice that of the 3.0 ecoDiesel
- Noisy during regen; during regen the exhaust is louder, when if first happened she took it into the dealer, she thought something was wrong
- Underpowered at high speeds, crossing Montana; speeds north of 80mph (speed limit is 80), the diesel starts to be apparent after say 70mph (the escalade was better, the x5 significantly better)
- Intermittent turbo lag, the truck can get confused and exhibit a goofy lag from a stop and go situation (ecoDiesels do this crazy bad, no where near that bad)
- Auto off, its annoying but that is an opinion, the pain point is that it gets confused and will restart the truck when it doesn't need to (parking and not get it into park quick enough) or it'll lurch forward on restart (if it stops and starts on a hill)

Pros
- Crazy quiet at idle, even compared to the ecoDiesel, this DMax is super quiet
- Town driving responsiveness, the massive amounts of torque at low speeds (< 40mph) is awesome; why better then the ecoDiesel
- Mileage, very good, better then the ecoDiesel better then 20mpg in town, approaching 30mpg on regular highways (60mph), mid 20's at interstate (85mph) speeds
- Range, getting ~700 miles out of a tank is slick

Comparing to the ecoDiesel the DMax is more responsive in town and at low speeds but is less powerful when passing at high speeds. The DMax is much quieter at idle, but does use alot more DEF per mile driven. The DMax gets about 2mpg better across the board, both running the same oversized BF AT's.

All considered from the perspective of driving she would rebuy this same vehicle again. She would also buy the diesel again, she really likes the massive range and doesn't like stopping at gas stations (the escalade and the x5 where pigs). This diesel seems to always have fuel in the tank.
 

Stbentoak

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I had an EcoD previous to this vehicle too, and I can say the Denali/Dmax is much more refined. I really did like my Eco, put over 100K on a Grand Cherokee with no real show stopping problems. But so far the Dmax outshines it in most every area. I've never got 700 miles from a tank tho, I just did 1500 miles in mine and 600 was about as good as we could do at 80-85 MPH. But a smooth vehicle that is a joy to road trip in....
 

ivin74

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How often do y 'all fill up the DEF tank? approximately in miles please, Thx
 

Pro299

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How often do y 'all fill up the DEF tank? approximately in miles please, Thx
I had the first oil change at 3500 miles and the dealer topped off the DEF. It was down two bars at the time, so must have been between two and three gallons to refill. Rough guess, a gallon per 1200 or so miles. No towing involved.
 

CTown Duramax

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2,000 miles. Dealer gave me half a tank of DEF and I put in another gallon to bring it to 3/4 full and the gauge has stayed there at 3/4.
 
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steiny93

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Wife's dmax has 7200 miles on it, at new it was full of def, I have added 2 of the 2.5 gallon jugs. It is 2 bars down from full.
Zero towing, greater then 1/2 the miles have been large road trips (> 500 miles).
I'd guess 5.5 gallons of def to 7200 miles.
 
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