"How reliable is the 2021 Gmc Sierra 3500?"

"Based on 27 NHTSA complaints, the 2021 Gmc Sierra 3500 has a median complaint mileage of 0 miles. The most common issue is Power Train."

"What are common problems with the 2021 Gmc Sierra 3500?"

"The most frequently reported component in NHTSA complaints for the 2021 Gmc Sierra 3500 is Power Train, accounting for a significant portion of the 27 total complaints filed."

2021 Gmc Sierra 3500: Reliability Data

Source: NHTSA — 27 complaints

Total Complaints

Power Train

Top Issue

Crash Reports

What Fails?

Most reported component issues from NHTSA complaints.

Power Train

Service Brakes

Electrical System

Engine

Unknown Or Other

Fuel/Propulsion System

Body

Tread/Belt

Back Over Prevention

Defroster/Defogger/Hvac System

Severity Assessment

Crashes

Fires

Injuries

Deaths

Sample Complaint Reports

"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. GMC is aware of issue, but has not provided a sol..."

"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..."

Source: NHTSA ODI Complaints Database. Names and identifying details omitted.

When Were Complaints Filed?

Number of complaints by the year the issue occurred.

Where Are Complaints Coming From?

Top states by complaint count.

CO: 7 CA: 4 ID: 3 WA: 2 OR: 2 WI: 2 FL: 1 NY: 1 NC: 1 MI: 1

Gmc Sierra 3500 — Other Years

See how this model compares across different model years.

Year	Complaints	Median Mileage	Top Issue	Crashes
1999	25	60,000	Antilock/Traction Control/Electronic Limited Slip	1
2000	30	57,007	Service Brakes, Hydraulic	3
2001	44	61,580	Antilock/Traction Control/Electronic Limited Slip	3
2002	29	101,000	Service Brakes	3
2004	29	87,000	Service Brakes	0
2005	29	46,000	Service Brakes	0
2008	26	70,500	Air Bags	0
2011	24	97,500	Air Bags	0
2015	40	43,000	Exterior Lighting	1
2016	27	63,750	Service Brakes	0
2020	72	28,700	Power Train	6
2022	37	40,000	Electrical System	6
2023	34	79,000	Power Train	4
2024	58	20,000	Power Train	0

Data source: View this vehicle on NHTSA.gov | NHTSA ODI Complaints Database. Public domain.

Methodology: Complaint counts and mileage distributions are computed directly from consumer-reported NHTSA complaints. This data represents reported issues, not failure rates — vehicles without complaints are not represented. Full methodology.

Data through: 2026-03-28