27 problems have been reported for the 2021 GMC Sierra 3500. The following chart shows the 10 most common problems for 2021 GMC Sierra 3500. The number one most common problem is related to the vehicle's power train with 7 problems. The second most common problem is related to the vehicle's electrical system (4 problems).
| Problem Category | Number of Problems |
|---|---|
| Power Train | |
| Electrical System | |
| Service Brakes | |
| Equipment | |
| Engine And Engine Cooling | |
| Other Fuel System | |
| Structure | |
| Visibility | |
| Back Over Prevention | |
| Tire |
In our research we use the PPMY index to compare the reliability of vehicles. The PPMY index of a certain model is defined as the problems reported per thousand vehicles per Year. The total sales of the 2021 GMC Sierra 3500 in the United States are 16,428 units [1]. If the total number of problems reported by GMC Sierra 3500 owners in the last 4 years is 27, and the age of the vehicle is 4, the PPMY index can then be calculated as
PPMY Index = 27 / 16,428 / 4 * 1000 = 0.41.
For more information, refer to this page: A study of reliability comparison across GMC Sierra 3500 model year vehicles.
The following chart shows the number of problems reported during each of the service years since the debut of the 2021 GMC Sierra 3500 in 2021.
| Service Year | Number of Problems |
|---|---|
| 2025 | |
| 2024 | |
| 2023 | |
| 2022 | |
| 2021 |
When making the decision between buying a new or used GMC Sierra 3500, the following table can be used to compare the 2021 GMC Sierra 3500 with the GMC Sierra 3500 from other model years. Note that the number of problems reported for the 2021 Sierra 3500 is 27 while the average number of problems reported for the 30 model years of the GMC Sierra 3500 is 21.