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2021 Gmc Sierra 3500 Recalls, Issues & Maintenance

The 2021 Gmc Sierra 3500 carries 5 open NHTSA recalls — most recently covering control module and seat belts. Owners report 7 recurring issue clusters, led by “Transmission failure and unintended gear shift.” GMC trucks and SUVs use the GM Oil Life System (OLS) — the same algorithm as Chevrolet. Because GMC's lineup is exclusively trucks and SUVs, severe-service intervals apply to most owners (towing, hauling, off-roading). The schedule below surfaces the items most relevant to GMC's truck-focused buyer.

5 Open Recalls

Source: NHTSA

SERVICE BRAKES, HYDRAULIC:POWER ASSIST:ELECTRIC:CONTROL MODULE

Campaign #21V758000 · Sep 29, 2021

Issue: General Motors, LLC (GM) is recalling certain 2021-2022 Chevrolet Silverado 2500, Silverado 3500, GMC Sierra 2500, and Sierra 3500 vehicles with electronic brake control modules (EBCM) replaced during vehicle assembly. The bolts that attach the brake pressure modulator valve (BPMV) assembly may not be properly tightened, which could fail to seal the two sub-assemblies and allow water intrusion.

Risk: Water in the BPMV may cause an electrical short circuit and increase the risk of fire.

Fix: Owners are advised to park outside and away from other structures until the recall repair is completed. Dealers will replace the BPMV assembly, free of charge. Owner notification letters were mailed on October 20, 2021. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N212349181.

SEAT BELTS

Campaign #20V792000 · Dec 17, 2020

Issue: General Motors, LLC (GM) is recalling certain 2019-2021 Chevrolet Silverado 1500 and GMC Sierra 1500, 2021 Chevrolet Suburban and Tahoe and GMC Yukon XL and 2020-2021 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles. The seat belt brackets may not be secured to the seat frame in the front-row center seating position.

Risk: If a seat-belt bracket is not secured, the seat belt may not properly restrain an occupant in the front-row center seat position, increasing the risk of injury in a crash.

Fix: GM will notify owners, and dealers will inspect left-side and right-side front-row center seat-belt bracket attachments and reassemble it correctly as necessary, free of charge. The recall began January 26, 2021. Owners may contact GMC customer service at 1-800-462-8782, Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N202314670.

SEAT BELTS

Campaign #20V811000 · Dec 23, 2020

Issue: General Motors, LLC (GM) is recalling certain 2020 Chevrolet Bolt EV and 2021 GMC Canyon and Sierra 1500, 2500 and 3500, Yukon, Yukon XL, Cadillac Escalade and Escalade ESV and Chevrolet Blazer, Camaro, Colorado, Equinox, Silverado 1500, 2500 and 3500, Suburban and Tahoe vehicles. Incorrect bolts may have been used at one or more fastening locations to secure the seat belts to the vehicle. If an incorrect bolt was used, the seat belt may not be properly attached to the vehicle.

Risk: If a seat belt assembly is not properly attached to the vehicle, the seat belt may not properly restrain an occupant in the event of a crash, increasing the risk of injury.

Fix: GM will notify owners, and dealers will replace the suspect bolts, free of charge. The recall began January 29, 2021. Owners may contact GMC customer service at 1-800-462-8785, Cadillac customer service at 1-800-458-8006, or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N202322230.

LATCHES/LOCKS/LINKAGES:TAILGATE:LATCH

Campaign #24V060000 · Jan 2, 2024

Issue: General Motors, LLC (GM) is recalling certain 2020-2024 Chevrolet Silverado 2500, 3500, GMC Sierra 2500 and 3500 vehicles equipped with power-unlatching tailgates. The tailgate's electronic gate-release switch may short circuit due to water intrusion, which can result in the tailgate inadvertently unlatching while the vehicle is in park.

Risk: An unlatched tailgate may open while driving and result in a loss of unsecured cargo, creating a road hazard and increasing the risk of a crash.

Fix: Owners are advised to check that the tailgate is closed and latched before driving. Dealers will replace the exterior touchpad switch assemblies, free of charge. Owner notification letters were mailed May 17, 2024. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N232426400.

POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE

Campaign #24V797000 · Oct 24, 2024

Issue: General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control valve may fail and cause the rear wheels to lock-up.

Risk: Rear wheel lock-up can increase the risk of a crash.

Fix: Dealers will install new transmission control module software, free of charge. GM will provide a special coverage program to cover the repair of transmissions that are identified by the remedy software as containing a defective control valve. Owner notification letters were mailed December 12, 2024. Owners may contact GM customer service at 1-888-988-7267, Cadillac customer service at 1-800-458-8006, GMC customer service at GMC 1-800-462-8782 or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N242454440.

Recall data refreshed Sep 13, 2026.

Known issues for this vehicle

What drivers and federal regulators have officially reported about the 2021 Gmc Sierra 3500.

Reported to NHTSA

Transmission failure and unintended gear shift

POWER TRAIN

5 NHTSA complaints · 2022-04-03 → 2025-11-24

“During takeoff the transmission acted as if it was in neutral while I was crossing traffic luckily, the semi truck that was coming towards me was able to stop. I had the vehicle towed to a shop. After the vehicle was towed to the shop the transmission acted normal when the…”
— Owner report, NHTSA ODI #11701315
“While driving 55mph on a 2 lane road, pulling a 5th wheel camper, the truck transmission downshifted by itself to a low gear. This caused a scary and immediate deceleration from 55 to 25mph. The trailer wanted to push into the oncoming lane the deceleration was so fast”
— Owner report, NHTSA ODI #11617429
“The contact stated while her son was driving at an undisclosed speed uphill, the vehicle failed to shift to a gear higher than 5th gear. Additionally, the rear wheels locked up, causing the vehicle to come to a stop. The driver attempted to resume driving, but the vehicle failed…”
— Owner report, NHTSA ODI #11638908

Read all complaints on NHTSA →

Diesel exhaust fluid system malfunction and speed restriction

FUEL/PROPULSION SYSTEM

4 NHTSA complaints · 2022-01-10 → 2024-11-01

“Multiple instances of diesel engine emissions system parts and software failure. While driving, towing or not, the DIC would randomly display a message that the DEF level is low and reduced speed will occur in x-amount of miles and that mileage would then begin a visible…”
— Owner report, NHTSA ODI #11623109
“I was told there were issues with the heater and pump. The heater turns high or the heater won’t work; and there are issues with the connector.02/24/22: My truck has 16,000 approx. miles. The check engine light came on and displayed message that I had so many miles until truck…”
— Owner report, NHTSA ODI #11459422
“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…”
— Owner report, NHTSA ODI #11454519

Read all complaints on NHTSA →

Service brake pedal loss and caliper seizure

SERVICE BRAKES

4 NHTSA complaints · 2021-10-26 → 2024-04-19

“With 42,774 miles on the vehicle, and the onboard monitor for brake wear showing remaining brake life at 94% front and 96% rear, brake fluid reservoir between Max and Min the brake pedal went soft and the vehicle would not stop. I resorted to putting the vehicle in neutral and…”
— Owner report, NHTSA ODI #11584171
“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”
— Owner report, NHTSA ODI #11438295
“The contact stated that while the vehicle owner was driving at an undisclosed speed, the driver noticed that the rear wheels were attempting to lockup. The contact stated that the failure was noticeable while driving forward and while reversing. No warning light illuminated”
— Owner report, NHTSA ODI #11743698

Read all complaints on NHTSA →

Backup camera and infotainment screen loss of image

BACK OVER PREVENTION

2 NHTSA complaints · 2025-05-12 → 2025-08-14

“The contact stated that while reversing, the back over prevention camera screen displayed an image of the ground. The contact stated that the image was approximately ten feet behind the vehicle. The vehicle was taken to the dealer; however, the failure was not duplicated”
— Owner report, NHTSA ODI #11680762
“There is a known issue with these trucks with the infotainment screen blacking out, which renders the backup cameras inoperative. This is a huge safety risk and its astounding to me that this hasn't been recalled yet”
— Owner report, NHTSA ODI #11660333

Read all complaints on NHTSA →

Rear defroster activation causing plastic melting and smoke

ELECTRICAL SYSTEM, VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM

1 NHTSA complaint · 2025-09-08 → 2025-09-08

“The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting…”
— Owner report, NHTSA ODI #11685740

Read all complaints on NHTSA →

Trailer brake wiring connection intermittent disconnect

ELECTRICAL SYSTEM, SERVICE BRAKES

1 NHTSA complaint · 2021-06-10 → 2021-06-10

“Trailer brake wiring connection continually disconnectsthen reconnects some time later. Some periods of up to 10 minutes without having trailer braking power. Major safety issue when toeing fifth wheel trailer. We lost brakes going down steep grades”
— Owner report, NHTSA ODI #11420443

Read all complaints on NHTSA →

Rear tire tread separation on highway

TIRES:TREAD/BELT

1 NHTSA complaint · 2023-05-24 → 2023-05-24

“The right rear tire (Goodyear Wrangler 275/65R20) separated and blew out on the highway, the truck was very difficult to control however it was safely stopped and there were no injuries. There was no observed warning prior to the blow out. The tire separation caused damage to…”
— Owner report, NHTSA ODI #11523697

Read all complaints on NHTSA →

Note: NHTSA also opened 1 defect investigation(s) on this vehicle that closed without action.

Issues on other model years

Source: NHTSA Office of Defects Investigation (ODI). Complaint data refreshed Sep 17, 2026. Investigation data refreshed Sep 17, 2026.

We display NHTSA's record with attribution; we don't editorialize on what these complaints mean for any specific vehicle.

Essential maintenance

Critical for safety and preventing major damage

Engine Oil & Filter (per Oil Life System)

Every 7,500 mi

Change oil when OLS reaches 0% or every 12 months. dexos1-approved synthetic required on Sierra 1500 5.3L/6.2L; dexos2 specified on Duramax diesel.

Estimated cost — typical U.S. ranges

Dealer

~$120–$160

Shop

~$85–$115

DIY

~$25–$55

Full synthetic costs more than conventional. 5-quart 0W-20 + filter is the typical bill.

Tire Rotation

Every 7,500 mi

Rotate tires every 7,500 miles. Sierra and Yukon owners running 4x4 should rotate every 5,000-7,500 miles to even out drivetrain wear.

Estimated cost — typical U.S. ranges

Dealer

~$85

Shop

~$60

DIY

Free

Often free at the shop where you bought the tires — worth asking before paying.

Brake Inspection

Every 7,500 mi

Inspect pads, rotors, and parking brake every 7,500 miles. Towing accelerates pad wear by 30-50%; check more often if towing regularly.

Estimated cost — typical U.S. ranges

Dealer

~$85

Shop

~$60

DIY

Free

Most shops do this free as a courtesy with any service. Don't pay separately if you can avoid it.

Brake Fluid

Every 45,000 mi

DOT 3 brake fluid: test annually, replace when moisture exceeds 3% or fluid is darker than copper.

Estimated cost — typical U.S. ranges

Dealer

~$180–$200

Shop

~$125–$140

DIY

~$10–$25

DOT 3 or 4 — match the cap. Vacuum bleeders make this a one-person DIY.

Important maintenance

Keeps your vehicle running smoothly and efficiently

Engine Air Filter

Every 45,000 mi

Long-life cellulose filter rated 45,000 miles. Trucks driven on unpaved roads or construction sites should inspect at every oil change.

Estimated cost — typical U.S. ranges

Dealer

~$60–$95

Shop

~$45–$70

DIY

~$15–$40

5-minute job on most cars; the airbox lid usually has clips, no tools needed.

Automatic Transmission Fluid

Every 45,000 mi

Severe service (towing 5,000+ lbs regularly, heavy stop-and-go): every 45,000 miles. Normal: 97,500 miles. Use Dexron-VI for 6L80/6L90, Mobil 1 LV ATF HP for 10L80/10L1000.

Estimated cost — typical U.S. ranges

Dealer

~$330–$500

Shop

~$235–$355

DIY

~$60–$180

Some sealed transmissions have no dipstick — fill is precise and best left to a shop. Many drivers can still DIY drain-and-fill.

Transfer Case Fluid (4WD)

Every 45,000 mi

Sierra and Yukon 4WD: replace every 45,000 miles. Use GM Auto-Trak II for active 4WD; GM 9986115 for selectable 4WD.

Estimated cost — typical U.S. ranges

Dealer

~$105–$140

Shop

~$75–$100

DIY

~$15–$40

AWD/4WD vehicles only. Easy drain-and-fill on most platforms.

Differential Fluid (front + rear)

Every 50,000 mi

Replace front and rear axle fluid every 50,000 miles, or 25,000 miles if towing. G80 limited-slip rear axles require GM friction-modifier additive.

Estimated cost — typical U.S. ranges

Dealer

~$150–$195

Shop

~$105–$135

DIY

~$20–$50

Drain plug + fill plug — straightforward DIY. AWD vehicles have two; budget for both.

Spark Plugs

Every 100,000 mi

Iridium spark plugs on the L83/L84 5.3L and L86/L87 6.2L V8 are rated 100,000 miles. AFM/DFM cylinder deactivation can cause uneven plug wear — check at 75,000 miles.

Estimated cost — typical U.S. ranges

Dealer

~$285–$390

Shop

~$200–$275

DIY

~$25–$100

Iridium plugs cost more but last 100k+ miles. V6/V8 access varies wildly — some are tough.

Dex-Cool Engine Coolant

Every 50,000 mi

Dex-Cool (orange): first change at 150,000 miles or 5 years, then every 50,000. Duramax diesel uses ELC (red) — different chemistry, do not mix.

Estimated cost — typical U.S. ranges

Dealer

~$285–$330

Shop

~$200–$235

DIY

~$25–$60

Use the manufacturer-specified coolant — wrong color/chemistry can damage the cooling system.

Recommended maintenance

Extends the life of your vehicle and improves comfort

Cabin Air Filter

Every 22,500 mi

Replace cabin air filter every 22,500 miles. Sierra HD and Yukon XL owners in dusty work environments should replace at 15,000 miles.

Estimated cost — typical U.S. ranges

Dealer

~$60–$95

Shop

~$45–$70

DIY

~$15–$40

Usually behind the glovebox. Shops charge labor for a 10-minute job — easy DIY win.

Fatal crash history & reported problems

Occupant deaths in fatal crashes (FARS)

28 crashes 2010–2024

FARS counts every occupant death in a fatal crash, whatever the cause — it does not mean the vehicle was at fault or defective. Counts are not adjusted for how many of each vehicle are on the road. How to read this number

Owner-reported problem signals

Separate from the federal fatality data above: complaints owners filed with NHTSA about this year and model. These are reports of problems, unverified, and are counted here only as signals.

0

complaints mentioning a crash

0

complaints mentioning a fire

Reviewed known issues for this vehicle·Open recalls for this vehicle

Typical U.S. ranges. Actual quotes vary by shop, parts choice, and vehicle condition.

How we estimate: Dealer = OEM parts × 1.4 + labor × $165/hr. Shop = parts + labor × $115/hr. DIY = parts only.

This maintenance schedule for the 2021 Gmc Sierra 3500 reflects GMC's published service intervals and the Oil Life System system. Your actual service needs may vary based on driving conditions, climate, and vehicle usage. Always consult your owner's manual for model-specific recommendations.

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