The 2015 Sierra HD family lineup.

The 2015 Sierra HD family lineup

Four upper tie-downs in Sierra 3500 Denali HD make it easier to secure cargo.

Four upper tie-downs make it easier to secure cargo.

Sierra 3500 Denali HD comes standard with trailer-sway-control technology that helps you trailer with confidence.

Standard trailer-sway-control technology helps you trailer with confidence.

An available durable spray-in liner protects your truck bed from scratches and dents.

An available durable spray-in liner protects your truck bed from scratches and dents.

The bold, striking new 2015 Sierra 3500 Denali HD exterior design.

The bold, striking new 2015 Sierra 3500 Denali HD exterior design.