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.
Ask the AI about the GMC Sierra- Years
- 2007–present
- Generations
- 3
- Engines
- 12
- Verified faults
- 20
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)
3.0 Duramax transmission control-valve failure (2020-2022 diesel)
Symptoms: the rear wheels locking up unexpectedly while underway, traced to the transmission control valve
What to do: Diesel owners should check the VIN against NHTSA recall 24V797000, and the follow-up 26V083000 for trucks whose first fix didn't resolve it, and get the transmission control valve replaced.
- 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.
- Critical usually from 0 mi (0 km)
Battery B+ cable intermittent connection / arcing (2019-2020)
Symptoms: an unexplained stall while driving, or heat/arcing at the battery-to-alternator connection
What to do: If the VIN falls under NHTSA recall 19V888000, get the B+ cable inspected and replaced; a burning smell near the battery is not something to wait out.
- Critical usually from 0 mi (0 km)
Brake caliper bolts not heat-treated (2020)
Symptoms: reduced braking, a grinding or interference noise at a wheel, or an outright broken caliper bolt
What to do: Confirm the VIN against NHTSA recall 20V116000 and have the caliper bolts replaced — don't ignore a new brake noise or a pull to one side.
- Critical usually from 0 mi (0 km)
Driveshaft joint weld failure (2019-2020)
Symptoms: a sudden loss of drive, or a new clunk/vibration underneath, from a driveshaft joint separating
What to do: Have the driveshaft weld checked under NHTSA recall 20V650000 — treat a new driveline clunk as worth investigating, not living with.
- Critical usually from 0 mi (0 km)
EBCM software silently disables ABS/ESC or brake assist (2019)
Symptoms: stability control or ABS stops working, or electronic brake assist is disabled, with no warning light to flag it
What to do: This was two sequential recalls — a first software fix, then a follow-up correcting a defect the first fix introduced. Confirm with a dealer that the truck has the final remedy, not just the initial update.
- Critical usually from 0 mi (0 km)
Fuel pump missing a pressure regulator (2020 trucks)
Symptoms: a fuel odor, a visibly wet fuel-pump module, or — worst case — a fire near an ignition source from an over-pressurized, cracked pump
What to do: Check the VIN against NHTSA recall 19V837000; GM replaces the fuel pump free of charge. Don't dismiss a persistent fuel smell as normal.
- 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 |
K2XX (2014-2018) · 2014–2018
4.3 V6 EcoTec3 · 285 hp · 5.3 V8 EcoTec3 · 355 hp · 6.2 V8 EcoTec3 (Denali) · 420 hp
Known problems
- Critical usually from 0 mi (0 km)
Exhaust heat-shield melting plastic parts (2014 4.3/5.3)
Symptoms: a burning-plastic smell or visible melted trim near the exhaust on early-production trucks
What to do: Check the VIN against NHTSA recall 14V007000; the remedy corrects the exhaust-to-plastic clearance that caused this on 2014 4.3/5.3 trucks.
- Critical usually from 0 mi (0 km)
Power-steering assist loss (2015 trucks)
Symptoms: a sudden but temporary loss of electric power-steering assist — the truck still steers, but the wheel becomes noticeably heavy
What to do: Confirm the VIN against NHTSA recall 14V719000 and have the EPS module software updated — this is exactly the symptom GM's fix addresses.
- Critical usually from 62,000 mi (100,000 km)
AFM lifter failure (5.3 L83 / 6.2 L86, incl. Denali)
Symptoms: a top-end tick or knock, rough idle, and a misfire code on a specific cylinder, worsening to camshaft damage if ignored
What to do: The Denali's 6.2 L86 uses the same Active Fuel Management system as the 5.3 — a new top-end tick on either engine deserves a prompt lifter/cam inspection, not a wait-and-see.
- Worth watching usually from 12,000 mi (20,000 km)
A/C condenser leak (2014-2016)
Symptoms: gradually weakening air-conditioning performance or outright warm air, from a slow refrigerant leak at the condenser
What to do: GM extended coverage for this specific leak pattern — check whether the truck's VIN and in-service date still fall inside that window before paying for a condenser and recharge yourself.
- Worth watching usually from 25,000 mi (40,000 km)
8L90 8-speed shudder
Symptoms: a shudder or vibration at a steady highway cruise, or a hard clunk on the 2-3 upshift
What to do: A transmission fluid-and-filter service with the correct-spec fluid, plus a TCM relearn, resolves most cases — don't jump straight to assuming a failed torque converter without trying the fluid service first.
Service schedule
| Item | Interval | Notes |
|---|---|---|
| Engine oil & filter service | every 7,000 mi (12,000 km) or 12 months | GM's Oil Life Monitor sets the real interval — halve it for towing, heavy loads or mostly short trips |
| Cabin air filter | every 22,000 mi (36,000 km) | — |
| Automatic transmission fluid & filter Important | every 45,000 mi (72,000 km) | 6L80 across the 2014-2015 lineup and on the 4.3 V6 throughout; 8L90 arrives standard on the Denali 6.2 for 2015, reaches upper 5.3 trims by 2016 and is standard across the 5.3 range from 2017 — an earlier service helps head off torque-converter shudder |
| Engine air filter | every 45,000 mi (72,000 km) | — |
| Transfer case & axle fluids | every 45,000 mi (72,000 km) | 4WD trucks only |
| Spark plugs | every 98,000 mi (157,000 km) | the EcoTec3 V8s are rated for long-life iridium plugs on this interval; inspect sooner if you tow often |
| Dex-Cool coolant Important | every 149,000 mi (240,000 km) or 60 months | GM's long-life Dex-Cool; don't top up with a different coolant type |
| Brake fluid flush Important | every 36 months | — |
GMT900 (2007-2013) · 2007–2013
4.3 V6 (Vortec 4300) · 195 hp · 4.8 V8 (Vortec 4800) · 302 hp · 5.3 V8 (Vortec 5300, AFM) · 315 hp · 6.0 V8 (Vortec Max, 2007-2009) · 367 hp · 6.2 V8 (Vortec 6200, Denali) · 403 hp
Known problems
- Critical usually from 50,000 mi (80,000 km)
AFM lifter failure and cam damage (5.3/6.2 V8, Gen IV)
Symptoms: a top-end tick that grows louder with engine speed, a rough idle, a misfire code tied to one cylinder, and — left unaddressed — a scored camshaft
What to do: A stuck Active Fuel Management lifter doesn't fix itself — get a persistent tick checked before it scores the cam, including on Denali trucks with the 6.2, which shares the same AFM system as the 5.3.
- Critical usually from 109,000 mi (175,000 km)
Frame rail and underbody rust
Symptoms: surface-to-heavy rust on the frame rails, crossmembers or fuel-line brackets, occasionally severe enough to compromise a jack point
What to do: Get the frame looked at from underneath each winter if you're in a salt-belt state — pitted or flaking rust at a structural point, not just surface rust, is worth a proper inspection before towing or heavy loading.
- Worth watching usually from 40,000 mi (65,000 km)
Gen IV 5.3 (LC9) oil consumption
Symptoms: oil level falling noticeably between changes with no visible leak, most pronounced on aluminum-block 5.3s built after February 2011
What to do: Track the dipstick trend rather than the calendar — a worsening consumption pattern on this engine is a documented piston-ring wear issue, not normal break-in use, and running it low invites bearing damage.
- Worth watching usually from 93,000 mi (150,000 km)
4L60E transmission wear points
Symptoms: a slipping or flared shift, especially 2-3 or 3-4, harsh engagement into gear, or a shudder from the torque-converter clutch
What to do: The 3-4 clutch pack and TCC solenoid are this transmission's known failure points — stay on the fluid-service schedule, and get a truck that's already flaring under load looked at before it becomes a rebuild.
- Good to know
Dashboard cracking / warping
Symptoms: splits or a bulging dash pad, typically starting near the defroster vents, worse after repeated hot-cabin exposure
What to do: A cosmetic, slow-developing issue rather than a safety one — NHTSA reviewed the complaint volume on this generation and did not find grounds for a recall. A dash cover is the usual practical fix.
- Good to know usually from 59,000 mi (95,000 km)
Fuel-level sending unit drift
Symptoms: a fuel gauge that jumps around or reads emptier than the tank actually is
What to do: Usually a worn sending-unit contact rather than an actual fuel problem — inconvenient, not dangerous. Confirm with an actual fill-up before assuming the tank is really low, and replace the sending unit (often bundled with the fuel-pump module) if it's persistent.
Service schedule
| Item | Interval | Notes |
|---|---|---|
| Engine oil & filter service | every 7,000 mi (12,000 km) or 12 months | GM's Oil Life Monitor sets the real-world interval — treat 12 months as the backstop, and cut it in half for towing, plowing or mostly short trips |
| Cabin air filter | every 22,000 mi (36,000 km) | — |
| Automatic transmission fluid & filter Important | every 45,000 mi (72,000 km) | 4L60E on most of the range, 6L80 on crew-cab 5.3s from 2009 and on the 6.2 Denali; service sooner than the interval if you tow regularly |
| Engine air filter | every 45,000 mi (72,000 km) | — |
| Transfer case & axle fluids | every 45,000 mi (72,000 km) | 4WD trucks only — 2WD Sierra trims skip this service |
| Spark plugs | every 98,000 mi (157,000 km) | petrol engines only; the cylinder-deactivation 5.3/6.2 load their plugs harder, so an earlier check doesn't hurt |
| Dex-Cool coolant Important | every 149,000 mi (240,000 km) or 60 months | top up with Dex-Cool only — mixing coolant types is a documented cause of intake-gasket corrosion on this generation |
| Brake fluid flush Important | every 36 months | — |
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 |
| 4.3 V6 EcoTec3 K2XX (2014-2018) · 2014–2018 | 17 mpg (13.8 L/100 km) | 22 mpg (10.7 L/100 km) | 19 mpg (12.4 L/100 km) | EPA |
| 5.3 V8 EcoTec3 K2XX (2014-2018) · 2014–2018 | 16 mpg (14.7 L/100 km) | 22 mpg (10.7 L/100 km) | 18 mpg (13.1 L/100 km) | EPA |
| 6.2 V8 EcoTec3 (Denali) K2XX (2014-2018) · 2014–2018 | 15 mpg (15.7 L/100 km) | 21 mpg (11.2 L/100 km) | 17 mpg (13.8 L/100 km) | EPA |
| 4.3 V6 (Vortec 4300) GMT900 (2007-2013) · 2007–2013 | 14 mpg (16.8 L/100 km) | 19 mpg (12.4 L/100 km) | 16 mpg (14.7 L/100 km) | EPA |
| 4.8 V8 (Vortec 4800) GMT900 (2007-2013) · 2007–2013 | 14 mpg (16.8 L/100 km) | 19 mpg (12.7 L/100 km) | 16 mpg (14.7 L/100 km) | EPA |
| 5.3 V8 (Vortec 5300, AFM) GMT900 (2007-2013) · 2007–2013 | 14 mpg (16.8 L/100 km) | 20 mpg (11.8 L/100 km) | 16 mpg (14.7 L/100 km) | EPA |
| 6.0 V8 (Vortec Max, 2007-2009) GMT900 (2007-2013) · 2007–2013 | 13 mpg (18.1 L/100 km) | 17 mpg (13.8 L/100 km) | 15 mpg (15.7 L/100 km) | EPA |
| 6.2 V8 (Vortec 6200, Denali) GMT900 (2007-2013) · 2007–2013 | 12 mpg (19.6 L/100 km) | 18 mpg (13.1 L/100 km) | 14 mpg (16.8 L/100 km) | EPA |
Lab-cycle figures, each shown with the cycle it was measured under — the same car under EPA, WLTP, NEDC or JC08 can differ by up to 20%. Real driving always falls short of the declared figure: roughly 10–20% on an EPA rating, 15–30% on a WLTP or NEDC one. That gap is normal, not a fault.
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Frequently asked
What are the most common GMC Sierra problems?
The faults reported most often are: AFM lifter failure and cam damage (5.3/6.2 V8, Gen IV); Frame rail and underbody rust; Exhaust heat-shield melting plastic parts (2014 4.3/5.3). 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 service — 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. Real driving falls short of any lab figure — roughly 10–20% on an EPA rating, 15–30% on a WLTP or NEDC one — and 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.