2015 GMC Sierra
Common problems & what to know before you buy
Before you message the seller, know the documented failure patterns, repair cost exposure, and risk level for the 2015 GMC Sierra.
What to watch for on the 2015 GMC Sierra
AFM Lifter Collapse and Camshaft Damage
Active Fuel Management carries over on the EcoTec3 V8s, and so does collapsed lifter and camshaft wear. A tick at cold start and a misfire on a deactivating cylinder are the warning signs. Still the most expensive likely failure.
8L90 Torque Converter Shudder
Eight-speed trucks, particularly 2015-2018 with the 6.2, develop a shudder felt at light throttle between roughly 30 and 50 mph. GM addressed it with revised fluid and sometimes a torque converter replacement. Test specifically for it on a level road at steady throttle.
4 more known problems on the 2015 Sierra
Your guide shows all of them and which apply to the exact car, and what to ask the seller.
2015 GMC Sierra price ranges
Six-speed trucks sidestep the 8L90 shudder entirely and are the lower-risk choice for long-term ownership. Denali models with the 6.2 are much quicker and better equipped but combine both known issues, so documented transmission and lifter history matters most on exactly the trucks people most want.
Recalls on the 2015 GMC Sierra
Steering: electric power assist system
Electric power steering (EPS) assist may be lost momentarily, followed by a sudden return of EPS assist.
Service brakes: vacuum
The amount of vacuum created by the vacuum pump may decrease over time.
Service brakes: wheel speed sensor/tone ring
08-ratio rear axle and four-wheel drive.
6 more in the guide, with whether each one was done on the car you're looking at.
Source: NHTSA
What 818 owners reported
Source: NHTSA
2015 GMC Sierra at a glance
- Trims
- BaseDenaliSLESLT
- Engine
- 5.3L 8-Cylinder, 4.3L 6-Cylinder, 6.2L 8-Cylinder
- Transmission
- Automatic 6-spd, Automatic 8-spd
- Drivetrain
- RWD, 4WD
- Fuel
- Gasoline
- Body style
- Truck
GMC Sierra (K2XX) Buyer's Guide
Transmission Shudder and Continuing AFM Risk
The K2XX Sierra, sold from 2014 to 2018, brought the EcoTec3 engine family, a much better interior, and improved refinement over the GMT900. It is a genuinely good truck, and the two things to understand before buying are both well documented.
AFM continues. The 5.3-liter and 6.2-liter EcoTec3 V8s retain Active Fuel Management, and with it the collapsed lifter and wiped camshaft risk that defines this era of GM trucks. Oil consumption is generally better than the previous generation but not eliminated.
The eight-speed shudder. Trucks fitted with the 8L90 eight-speed automatic, mostly 2015 to 2018 and mostly with the 6.2, developed a well-known torque converter shudder felt as a vibration at light throttle around 30 to 50 mph. GM addressed it with revised transmission fluid and, in some cases, torque converter replacement. Six-speed trucks avoid it entirely.
What else to look for: Rust is much improved over earlier generations but still check rockers and cab corners on northern trucks. Air conditioning condenser failures are common. Check for the usual high-mileage suspension wear.
Reality check: A six-speed 5.3 with documented maintenance is the low-drama choice. A 6.2 with the eight-speed is much quicker and more likely to need transmission attention.
About the K2XX
The K2XX GMC Sierra, sold from 2014 to 2018, brought the EcoTec3 engine family, a considerably better interior, and improved refinement over the GMT900. It is a genuinely good truck carrying two well-documented issues. Active Fuel Management continues on the 5.3-liter and 6.2-liter V8s, and with it the collapsed lifter and camshaft damage risk, though oil consumption is generally better controlled than on the previous generation.
The second issue is transmission-specific. Trucks fitted with the 8L90 eight-speed automatic, predominantly 2015 to 2018 and most often with the 6.2, developed a torque converter shudder felt as a vibration at light steady throttle between roughly 30 and 50 mph, which GM addressed with revised transmission fluid and in some cases torque converter replacement. Six-speed trucks avoid it entirely and are the lower-risk choice for long-term ownership. Air conditioning condenser failures are common across the generation, and body rust, while much improved, still affects northern trucks at the rockers and cab corners. The trucks buyers most want, well-equipped Denali models with the 6.2 and eight-speed, are precisely the ones that combine both known issues.
Other GMC Sierra years
Free Car Finder
Still deciding on the 2015 GMC Sierra?
Answer a few quick questions and see your top 3 used cars, with the years to shop.
Frequently asked questions
How do I test for the transmission shudder?
Find a level road, get to roughly 30 to 50 mph, and hold a light steady throttle in a high gear. The shudder feels like driving over rumble strips or like the truck briefly running on a flat tire. It comes and goes with temperature, so a cold test drive may not reveal it.
Is AFM still a problem on the EcoTec3 engines?
Yes, though generally less severe than on the GMT900. The lifter and camshaft failure mode is the same. Cold-start ticking and heavy oil consumption remain the symptoms to watch for, and a documented repair or a properly executed delete is worth paying for.
Six-speed or eight-speed?
For used buying, the six-speed. It avoids the torque converter shudder entirely and has proven durable. The eight-speed shifts better when it is behaving, but it introduces the generation's second known issue on top of AFM.
Is the 6.2 worth it over the 5.3?
It is substantially quicker and tows more, and in Denali form it comes with the better equipment. It also mostly comes attached to the eight-speed and retains AFM, so it concentrates the risks. If you want the performance, buy one with documented history.
Squeezed is a buyer guide based on public data and industry patterns, not a mechanical inspection. Always get a professional pre-purchase inspection before you buy.