New spy photos have given us our first detailed look at the 2019 GMC Sierra 1500 Diesel.

Spy photographers caught this prototype testing in Colorado and managed to get photos of its underside, revealing its suspension setup. The photos also show the diesel exhaust fluid (DEF) tank and diesel particulate filter, confirming an oil burner will be offered on the next Sierra, just like the Silverado.

As for engine, there are still a few options the American automaker could be going with. Rumors suggest there’s a Navistar 3.0-liter six-cylinder diesel engine that’s a possibility, and GM has a 4.5-liter diesel V8 it could put into production. Another rumor has GM upgrading the turbocharger and injectors on its 2.8-liter four-cylinder diesel used in the Colorado and Canyon small pickups.

With the GMC Sierra 1500 moving to an aluminum body, the weight shed may allow a four-cylinder engine to offer adequate performance.

READ MORE: 2019 Chevy Silverado Diesel Confirmed in Spy Shots

Expect the standard gasoline engines to be refined for the new pickup, with a turbocharged V6 engine likely joining the lineup. The 10-speed automatic transmission found on the Camaro ZL1 is also expected on certain models.

The 2019 GMC Sierra should arrive late next year.

This article originally appeared on AutoGuide.com