GMC Sierra: common problems, service schedule and fuel economy
What typically goes wrong on the GMC Sierra, at what mileage, and what keeping it right involves — from Brimly's Vehicle Knowledge Base, where every fault is checked by a human before publication.
- Years
- 2019–present
- Generations
- 1
- Engines
- 4
- Verified faults
- 3
T1XX (2019+) · 2019–present
2.7 Turbo I4 · 310 hp · 3.0 Duramax diesel I6 · 277 hp · 5.3 V8 · 355 hp · 6.2 V8 · 420 hp
Known problems
- Critical usually from 0 mi (0 km)
6.2 V8 (L87) connecting-rod bearing failure (recall)
Symptoms: engine knocking or a sudden loss of power / seized engine, potentially with little warning
What to do: 2021-2024 trucks with the 6.2 L87 V8 were recalled for manufacturing defects in the connecting-rod bearings and crankshaft that can seize the engine. Check the truck against the recall and have the inspection/remedy completed; a deep knock or loss of power warrants stopping and getting it checked immediately.
- Worth watching
8-speed automatic shudder / harsh shifting
Symptoms: shudder or vibration felt like driving over rumble strips, plus harsh or clunky gear changes
What to do: The 8-speed automatic on early T1XX trucks can shudder, usually traced to the transmission fluid. A correct-specification fluid flush per GM's bulletin normally fixes it; have it done before assuming a bigger fault.
- Worth watching usually from 31,000 mi (50,000 km)
AFM/DFM lifter failure on the 5.3 and 6.2 V8
Symptoms: a loud tick or tapping, rough idle, misfire (often a specific cylinder) and a check-engine light; sometimes preceded by oil consumption
What to do: The cylinder-deactivation (AFM/DFM) lifters on the 5.3 and 6.2 V8 can fail, collapsing and damaging the camshaft. Do not keep driving on a persistent tick with a misfire — have it diagnosed early, since catching it before cam damage is far cheaper. Keep oil changes strictly on schedule.
Service schedule
| Item | Interval | Notes |
|---|---|---|
| Engine oil & filter change | every 7,000 mi (12,000 km) or 12 months | follow the oil-life monitor; halve for towing, heavy loads or short-trip use |
| Cabin filter | every 19,000 mi (30,000 km) | — |
| Air filter | every 28,000 mi (45,000 km) | — |
| Automatic transmission fluid important | every 93,000 mi (150,000 km) | service earlier (~75-100k km) if used for towing or in severe conditions — helps with 8-speed shudder |
| Spark plugs (petrol) | every 93,000 mi (150,000 km) | shorter on the 2.7 turbo; not applicable to the diesel |
| Brake fluid important | every 36 months | — |
| Timing chain inspection | — | all engines are chain-driven — inspect for noise rather than on a fixed interval |
Manufacturer-declared fuel economy
| Engine | City | Highway | Combined | Cycle |
|---|---|---|---|---|
| 2.7 Turbo I4 T1XX (2019+) · 2019–present | 18 mpg (13.1 L/100 km) | 21 mpg (11.2 L/100 km) | 19 mpg (12.4 L/100 km) | EPA |
| 3.0 Duramax diesel I6 T1XX (2019+) · 2019–present | 22 mpg (10.7 L/100 km) | 26 mpg (9 L/100 km) | 24 mpg (9.8 L/100 km) | EPA |
| 5.3 V8 T1XX (2019+) · 2019–present | 15 mpg (15.7 L/100 km) | 19 mpg (12.4 L/100 km) | 17 mpg (13.8 L/100 km) | EPA |
| 6.2 V8 T1XX (2019+) · 2019–present | 15 mpg (16.2 L/100 km) | 19 mpg (12.4 L/100 km) | 16 mpg (14.7 L/100 km) | EPA |
Lab-cycle figures, each shown with the cycle it was measured under — the same car under WLTP, NEDC, EPA or JC08 can differ by up to 20%. Real-world consumption typically runs 15–30% above the declared number, and that gap is normal, not a fault.
Ask about the GMC Sierra
The car is already selected — ask anything. Answers draw on the same verified data as this page. Ten questions a day, no sign-up.
The assistant is answering…
That's 10 for today
The free web limit resets tomorrow. In the Brimly app the assistant knows your specific car — its real mileage, fuel log, and service history.
Requires iOS 18.1 or later. Free to download, with optional in-app purchases.
The conversation is stored only in your browser — we don't keep it on our servers.
A starting point, not a diagnosis: this page describes what tends to happen to this model, and a workshop confirms what is happening to your car.
Track your own car, not the model average
Brimly logs your fill-ups, mileage and service history on your iPhone — and its assistant answers about your car, with its numbers.
Requires iOS 18.1 or later. Free to download, with optional in-app purchases.
Frequently asked
What are the most common GMC Sierra problems?
The faults reported most often are: 6.2 V8 (L87) connecting-rod bearing failure (recall); 8-speed automatic shudder / harsh shifting; AFM/DFM lifter failure on the 5.3 and 6.2 V8. Symptoms, the mileage each appears at and what to do about it are all above.
How often does the GMC Sierra need servicing?
Engine oil & filter change — every 7,000 mi (12,000 km) or 12 months. The full published schedule is above; your car's own service book always takes precedence.
What is the real fuel consumption of the GMC Sierra?
The manufacturer declares 19 mpg (12.4 L/100 km) combined for the 2.7 Turbo I4 under the EPA cycle. In real use expect 15–30% more — that gap is normal.
Where does this data come from?
Brimly's Vehicle Knowledge Base — the same verified facts the app's AI assistant answers from. Every fault is written up from public sources and then checked by a human before it is published; nothing here is generated on the fly.