The 2015 GMC Sierra with the 5.3-liter V8 uses a six-speed automatic transmission—the Hydra-Matic 6L80.
Context for the Sierra's drivetrain
For the 2015 model year, GM paired the 5.3-liter EcoTec3 V8 with the Hydra-Matic 6L80 six-speed automatic. This combination was standard on most Sierra 1500 trucks equipped with the 5.3L, and it was used across both two-wheel drive and four-wheel drive configurations. The 6L80 is a member of GM’s Hydra-Matic family and was chosen for a balance of smooth shifting, towing capability, and overall efficiency in light-duty pickup duty.
Key specifications and behavior
Before listing the main features and capabilities, it helps to know what to expect from the 6L80 in this truck lineup.
- Transmission name: Hydra-Matic 6L80, a six-speed automatic with overdrive
- Electronic control with Tow/Haul mode and adaptive shifting
- Designed to handle the torque output of the 5.3L EcoTec3 V8
- Used across both 2WD and 4WD Sierra 1500 configurations in this model year
- Part of GM's Hydra-Matic family of transmissions
In practice, the 6L80 provides smooth upshifts, confident highway performance, and adequate towing capability for typical light-duty use.
Summary
For the 2015 GMC Sierra with the 5.3L V8, the standard transmission is the Hydra-Matic 6L80 six-speed automatic. This pairing defined the truck’s driveline for that model year, delivering a balance of efficiency, comfort, and capability for everyday and toward-tow duties.
What transmission is in a 2015 GMC Sierra 1500 6-speed?
6L80 2014-2018 Chevy/GMC Silverado and Sierra 1500 – Remanufactured 6-Speed Automatic Trans.
What transmission does a 2015 GMC Sierra 5.3 L have?
V6- and 5.3-liter V8-powered models have a six-speed automatic transmission, while those with the larger V8 have an eight-speed automatic. With the base engine and rear-wheel drive, the 2015 Sierra gets an EPA-estimated 18/24 mpg city/highway, which is on par with that of rivals.
How do I tell what transmission I have on my GMC Sierra 1500?
As I push that plus. And I go up to second gear third gear fourth gear i'm pushing the plus. You see the plus fifth gear sixth gear seventh gear eighth gear that means it's an 8-speed.
What kind of transmission does a 5.3 Vortec have?
In all applications, the engine is matched with GM's Hydra-Matic 6L80 six-speed automatic transmission. The 5.3L's balance of performance and efficiency is great airflow throughout.