In brief, the 2018 Silverado 1500 offered multiple transmissions depending on the engine: a 6-speed automatic with the 4.3L V6; 8-speed automatics with the 5.3L and 6.2L V8s; and a 10-speed automatic with the 3.0L Duramax diesel.
The Silverado's powertrain lineup varied by trim and configuration, so the exact transmission you’d get could depend on the chosen cab/bed setup and whether you opted for the diesel. This kept several combinations available across the model year while aligning with performance and efficiency targets for different driving needs.
Transmission options by engine
Gasoline engines offered in 2018 were paired with 6- or 8-speed automatics depending on the engine. The diesel engine used a 10-speed automatic.
Gasoline engines
Before listing the gasoline configurations, note that the following pairings were common across the gasoline-powered Silverado 1500 trims in 2018:
- 4.3L V6 EcoTec3 — 6-speed automatic
- 5.3L V8 EcoTec3 — 8-speed automatic
- 6.2L V8 EcoTec3 — 8-speed automatic
In gasoline-powered configurations, Chevrolet matched the base V6 with a 6-speed automatic and the larger V8 options with an 8-speed automatic to balance performance and efficiency across the lineup.
Diesel option
The Duramax turbo-diesel was paired with a 10-speed automatic, which boosted both towing capability and highway efficiency for diesel-equipped pickups.
- 3.0L Duramax Turbo-Diesel — 10-speed automatic
The diesel powertrain maintains strong torque delivery and refined highway operation thanks to the 10-speed transmission.
Summary
For the 2018 Chevy Silverado 1500, transmission options depended on the engine: a 6-speed automatic with the 4.3L V6; 8-speed automatics with the 5.3L and 6.2L V8s; and a 10-speed automatic with the 3.0L Duramax diesel. Always verify the exact configuration for a given truck, as trims and market availability can vary.