Used 2021 GMC Sierra 1500 Diesel Consumer Reviews
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Broke down at 1,236 miles
Let down, 01/16/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
80 of 90 people found this review helpful
Bought a 2021 AT4 with 3.0L Duramax. Ordered it and waited 4 months for it to arrive. Love the ride & engine. Had to be towed to dealer with 1,236 miles due to a "transmission module issue." Been 3 days haven't heard back. Think transmission might've blown. Wouldn't go in reverse, would go into reverse position but wouldn't move. Engine power was reduced & check engine light came on. The 10 speed transmission was supposed to be solid.... be cautious
Very pleasing to drive.
Howard Beck, 10/13/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
14 of 15 people found this review helpful
Have 6,000 miles on and not a single problem. Handles great. Love the multi-pro tailgate, makes it so easy to use truck. interior is easy to use all to options. Have the 3.0L great power. Wish I could turn off completely the auto off feature.
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2021 GMC Sierra 1500 for sale near you
Showing 3 of 186 listings
- SLT Diesel Crew CabMSRP: $44,0124 mi away
- Elevation Crew CabMSRP: $32,7544 mi away
- AT4 Crew CabMSRP: $39,42338 mi away
See all 186 listings
Great Pickup
Laban, 05/01/2021
updated 11/07/2022
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
15 of 21 people found this review helpful
GMC six cylinder deiseal is smooth, great towing, fuel efficient vehicle. But with Diesel $1.00 to $1.25 more than Regular gas - I am hurting.
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New truck big burner out pile of trash
Mark Dupont, 04/18/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
26 of 42 people found this review helpful
Bought a 2021 GMC Sierra sky. All the bells and whistles. Had it 5 months with 3400 miles. Came back from store and parked it in driveway. Went in the house and my wife said your truck is smoking. Ran out and flames under hood. Five minutes later entire front end of truck engulfed in flames. Total loss. I was just lucky I was out of it. No indication of problems while driving.
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GMC AT4 Diesel CarbonPro Series
Scott M, 03/16/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
13 of 24 people found this review helpful
You can't get a truck with more luxury, more add-ons, better mileage, and power. This thing rocks and overall, cannot be beat. I love it and I have only had it a couple of days. I cant wait to put it through it paces and see what else this thing can do. Thanks to Nyle Maxwell GMC located in Round Rock, Texas for an amazing on an amazing truck.
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Love it!
Boyd Bowers, 11/09/2022
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
1 of 1 people found this review helpful
I have the Diesel engine and absolutely love it!
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Can't get parts
Roger, 12/01/2022
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
1 of 1 people found this review helpful
Almost a month now can't get fuel pump
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So much better than anything Ford has
Shane, 01/04/2023
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
1 of 1 people found this review helpful
The ride, technology package, the way the seat sits compared to ford. Large backseat 34 miles per gallon with the diesel. Love it! They'll never be another Ford in my driveway:-)
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Dangerous truck
Disappointed , 03/02/2024
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
1 of 1 people found this review helpful
I have a 2021 GMC Sierra 1500 Elevation with the 3.0 Duramax and I can’t even pass a golf cart without it going into limp mode. There is a terrible issue in the relay between Engine and Transmission that every time I try and speed up it throws a code stating low oil pressure and another about timing yet when I go and get it looked at there is no issue they can find and to go through a full diagnostic it would take 3-6 months for a diesel mechanic to get to and there will be no loaner given in the meantime (warranty still in effect). When I try and speak to a certified mechanic with GM they go silent about this engine. I cannot even let my wife drive my truck because it is such a danger. This issue happens 5-10 times per week. To get it back on road I have to disconnect the negative on the battery and reconnect and then it is fine until I try and pass someone or speed up to quick. The turbo is practically useless in this truck and the so called towing power does not exist beyond an empty trailer. I cannot in good faith even sell this truck to someone knowing that it has such a dangerous issue. I have spoken to several people with this same truck (minus the elevation package) and they say they are having same issues but not in such intervals as myself. My advice, STAY AWAY FROM 3.0 DURAMAX.
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Did not get the GMC or Chevy 1500 truck
Ron, 06/18/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
12 of 53 people found this review helpful
I went to a few dealers. One dealer would not let me test drive the vehicle and said we have a few and take it or leave it. Others were nice, but did not have what I wanted. The chip thing shows we should make at least 50 percent of items here in the United States. As far as getting much off, forget about it, so not the right time to buy a vehicle.
Love this truck
LarryB, 12/10/2021
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
0 of 0 people found this review helpful
I have had it for only a month but every time I drive it I am amazed at how smooth and quiet it is and so are my friends and family that are along for the ride. I love the simplicity of the interior after all it is a truck. If I wanted fancy and flashy I would have bought a luxury vehicle. It has the right amount of everything as far as I am concerned. The infotainment display is plenty. It serves its purpose and gets the job done. I don't want a huge screen taking up my dash that I just choose settings and play music on. I am very happy so far! I love the multi pro tailgate and the Carbon Pro bed is a winner in my eyes!
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Great Pickup.
Mishell VO, 09/05/2022
2021 GMC Sierra 1500 AT4 4dr Crew Cab 4WD 6.6 ft. SB (3.0L 6cyl Turbodiesel 10A)
0 of 0 people found this review helpful
We have loved this pickup so much. Great mileage, so comfortable, great truck all around. We got hit by a drunk driver yesterday and I’m convinced the sturdiness of the truck saved us. The damage to ours vs his was nothing. We are buying another.
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