NHTSA (USA)Critical
At a glance
This page covers 8 recalls and 51 owner complaints for the 2020 GMC Sierra 3500.
Powertrain complaints dominate what owners of the 2020 GMC Sierra 3500 report, accounting for the largest share of filed issues by a wide margin. Transmission behavior is a recurring theme, with owners describing hard downshifts, delayed engagement, and the truck entering limp mode, in at least one case with no warning light preceding it. A failed transmission valve body sensor was identified as the cause in one of those incidents. Engine complaints also appear, including a report of the engine seizing at highway speed with no prior warning and an inability to restart. The diesel exhaust fluid system draws a handful of reports as well, with owners describing a malfunctioning DEF tank heater that damaged the tank and surrounding connectors. Electrical system complaints and tire-related reports round out the picture at lower volumes, without a single dominant symptom tying them together.
51
Total Complaints
4
Crash-Related
2
Fire-Related
1
With Injuries
By System
The 2020 GMC Sierra 3500 has 8 recalls, the most serious being a transmission control valve that can cause the rear wheels to lock up without warning, raising the risk of a crash.
Two of these recalls address the same transmission issue: one covers diesel-equipped trucks broadly, and the other specifically affects trucks where a prior repair attempt did not fully resolve the problem. On the safety equipment side, when the front seatbelt pretensioners fire in a crash, hot gas can escape through a gap in the pretensioner bracket and ignite the carpet, potentially causing a vehicle fire on trucks with carpet floor covering. The front-row center seatbelt bracket may also not be properly secured to the seat frame, meaning the belt may not hold an occupant in a crash. The curtain airbag inflator has a separate concern: a diffuser component can separate during deployment, reducing the airbag's ability to protect occupants.
The hood latch striker wire can fracture and allow the hood to fly open while driving; prior repair attempts under an earlier recall did not reach all affected trucks, so this issue appears under two separate campaigns. On the exterior, trucks with power-unlatching tailgates may experience water intrusion in the electronic release switch, causing the tailgate to unlatch on its own and drop open while driving, which can send cargo into traffic.
At a glance
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Complaints are owner-reported and reflect individual experiences, not confirmed defects. They are distinct from recalls. Data sourced from the national vehicle safety complaint database. See trending complaints →
What can fail
The transmission control valve may not have been repaired correctly under a previous recall, causing it to fail and lock up the rear wheels.
What the fix does
Dealers will inspect your vehicle and update the transmission control software at no charge.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The transmission control valve may fail, causing the rear wheels to lock up unexpectedly.
What the fix does
Dealers will install updated transmission control module software and repair or replace defective control valves as needed.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
Water can get inside the tailgate's electronic release switch and cause it to short circuit, making the tailgate unlatch on its own while parked.
What the fix does
Dealers will replace the exterior touchpad switch assembly at no cost to fix the electrical short and prevent unintended unlatching.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The seat belt brackets in the front-row center seating position may not be properly secured to the seat frame, reducing their ability to restrain occupants.
What the fix does
Dealers will inspect the seat belt bracket attachments on both sides and reassemble them correctly if needed, at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The diffuser on the roof-rail air bag inflator may not be properly crimped and could separate during air bag deployment.
What the fix does
Dealers will replace the roof-rail air bag modules at no cost.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
Hood-latch striker wires on replacement hoods may not be properly heat-treated, causing them to crack or break.
What the fix does
Dealers will replace the hood assembly at no cost. For counter-sale hoods, dealers will contact owners with replacement instructions.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
The wires in the hood latch may not have been properly heat-treated, which can cause them to crack or break.
What the fix does
The dealer will replace the entire hood assembly at no cost to you.
Summarized — see the official notice for exact wording, dates, and contacts.
At a glance
What can fail
When front seat belt pretensioners deploy, hot gas vents through an opening in the bracket and may ignite the carpet floor covering.
What the fix does
Dealers will close off the opening in the pretensioner bracket to prevent hot gas from reaching the carpet.
Summarized — see the official notice for exact wording, dates, and contacts.