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GMC Sierra 3500Model year report

2021 GMC Sierra 3500 Problems

Complaints
20filed with NHTSA
Median mileage
101,500miles, 4 complaints with mileage
Recalls
5campaigns on record
Trend
RisingComplaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.

Sources: NHTSA records for the 2021 GMC Sierra 3500 (complaints, recalls, investigations). Report an error

NHTSA recorded 20 consumer complaints for the 2021 GMC Sierra 3500. The part named most often is transmission and drivetrain, with 7 complaints (35% of the total), followed by brakes (5) and electrical system (4). 4 of the complaints include a mileage, and 25% of those were filed for vehicles with under 50,000 miles; the median is 101,500 miles. NHTSA lists 5 recall campaigns and 841 technical service bulletins for this model year. Transmission and drivetrain complaints overlap with 1 recall campaign covering the valves/valve body and 113 technical service bulletins filed under the same part. Brakes complaints overlap with 1 recall campaign covering the control module and 22 technical service bulletins filed under the same part.

This model year has fewer than 25 complaints on record, so the numbers below can change a lot with a few new reports.

Which parts are reported most

Complaints can name more than one part, so the counts add up to more than the total. Select a part to see its complaints, recalls and bulletins.

Example complaints

Transmission and drivetrain: “Transmission had to be replaced from the dealership. Hard shifting dealership said truck was 23 days out of warranty. I couldn’t get into the dealership that truck was purchased from for 3 weeks. Had to go to the Jeff Gordon dealership, which is Chevrolet. And I had to replace the transmission.”

NHTSA complaint #11636808, filed 2025-01

Brakes: “The vehicle recently had a recall repaired at the dealership. I subsequently took delivery on it as a BRAND NEW UNIT, and the brakes are extremely soft; to the point where I must depress the pedal to the floor to get it stopped even at slow speeds. I hoped it was just an air bubble from the repair; but the fluid levels are full and the dealer had no ideas on what could be wrong at this point. I have a great relationship with this dealer, and we’ll continue working on it. …”

NHTSA complaint #11438295, filed 2021-10

Electrical system: “When carrying the electronic key in my pocket the vehicle will lock/unlock presumably due to the remote contacting other items in the pocket. I have owned well over a dozen GM vehicles and never had this issue. I believe the remote design has the lock/unlock buttons too proud of the surrounding surface”

NHTSA complaint #11647111, filed 2025-03

Engine: “•The diesel exhaust fluid heater is a faulty component in the system, there is a back order on the part with no ETA • My pickup only does 55MPH right now and soon to do 5MPH you cannot drive on a public road doing 5MPH •There is thousands of other people having the same exact problem! •The DEF light is illuminated on my dash along with the check engine light, when you diagnose the error code it comes up with “P20C1 Reductant Heater C Control Circuit/OPEN””

NHTSA complaint #11454519, filed 2022-02

Mileage when problems were reported

25% of the 4 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 70,000 and 133,000 miles.

0%0–100%10–2525%25–5025%50–750%75–10050%100–1500%150+
Share of complaints by mileage when the problem was reported, in thousands of miles (4 complaints with mileage). Red bars: under 50,000 miles. Bucket widths differ. Median: 101,500 miles.

Complaints by year filed

Trend: rising. Complaints filed in the last 3 full calendar years are at least 25% higher than in the 3 years before.

2021202220232024202582026
Complaints by year the complaint was filed with NHTSA. Red bars: the last 3 full calendar years used for the trend. The current year (2026) is partial.

Recalls and investigations

Recall details for the 2021 GMC Sierra 3500 → · Check a VIN at nhtsa.gov/recalls

Technical service bulletins

TSBs are manufacturer notes to dealers about known repair procedures. They are not recalls and do not by themselves mean a vehicle has a fault. 841 on record; the latest 10 are shown.

See all 841 bulletins →

Other model years of the GMC Sierra 3500

YearComplaintsMedian miRecallsCrash ★MPGScore (50 = typical)Trend
202652,2502———Too new
20251740,0001———Too new
20245036,0003——Too new to compareToo new
20232833,8001——47 · TypicalToo new
20223231,1543——54 · TypicalRising
202120101,5005———Rising
20205128,7008——95 · MoreRising
20191353,0047———Not enough data
20181453,8006———Not enough data
20171321,0007———Not enough data
20161927,5007———Rising
20153138,5007——50 · TypicalFalling
2014768,0003———Not enough data
20131449,2184———Not enough data
2012931,2004———Not enough data
20112077,2505———Falling
2009536,6005———Not enough data
20082559,0003——0 · FewerFalling
20071636,0003———Rising
20061149,9740———Not enough data
20052450,5000———Rising
20042484,0000———Rising
2003760,5000———Not enough data
20022079,0002———Stable
20013663,5402——Not compared (before 2008)Falling
20002657,0072——Not compared (before 2008)Rising
19991959,5001———Stable
199812128,0002———Not enough data
19971095,0001———Not enough data

All GMC Sierra 3500 model years · Best and worst years by complaints

Frequently asked questions

How many NHTSA complaints does the 2021 GMC Sierra 3500 have?

NHTSA recorded 20 consumer complaints for the 2021 GMC Sierra 3500 as of Oct 28, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

What part of the 2021 GMC Sierra 3500 is reported most often?

Transmission and drivetrain is named most often, in 7 complaints (35% of the total), followed by brakes with 5.

Has the 2021 GMC Sierra 3500 been recalled?

NHTSA lists 5 recall campaigns for this model year. To check a specific vehicle, enter its VIN at nhtsa.gov/recalls.

At what mileage are problems with the 2021 GMC Sierra 3500 reported?

Among the 4 complaints that include a mileage, the median is 101,500 miles and the middle half falls between 70,000 and 133,000 miles; 25% were filed for vehicles with under 50,000 miles.

About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 28, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.

Complaint counts come from NHTSA’s public complaint database; we count each complaint once. The source records for this vehicle are on nhtsa.gov. Scores and trends are our own summaries of that data, described in the methodology. This page is not legal, safety or repair advice: for a specific vehicle, check its VIN at nhtsa.gov/recalls and ask a qualified mechanic. See an error? Tell us.