Chevrolet will offer its existing Silverado 1500 alongside its fourth-generation 2019 Silverado 1500 for a short period of time as the Silverado 1500 LD, according to Chevrolet's truck spokesman.

The 2019 Silverado 1500 LD will serve as a continuation run of the current generation pickup that will help "maintain production volume while also improving the launch quality of the new trucks," said Monte Doran, a Chevrolet spokesperson. The new-generation truck will be sold as the 2019 Silverado 1500.

Fleets will likely not be able to order the Silverado 1500 LD, which will mostly be sold based on what's availalable in dealer inventory. It will be mostly offered as LT crew cab models with popular equipment. Sales are expected to end in early 2019.

For its new Silverado 1500, Chevrolet has been rolling our various models, starting with the highest-volume sellers in August that include crew cabs, 5.3-liter V-8 pickups, and LT trim and above grades.

In November, Chevrolet began selling extended cab (Double Cab) trucks, 4.3-liter V-6, 2.7-liter inline-four-cylinder, and trims such as Work Truck, Custom, and Custom Trail Boss.

In January, Chevrolet will begin production of the regular cabs and pickups equipped with 3.0-liter turbodiesel inline-six-cylinder engines.