2021 Gmc Sierra 1500 Diesel Automatic Engine, Release Date, Rumor – With the new technology of this pickup truck out for 2021 year, the 2021 GMC Sierra 1500 is not delivering way too many changes. The approaching model may not have as many choices as we will like, so this might be a sector exactly where the vehicle may possibly develop. Latest features and perhaps additional trim amounts are usually all we can easily receive the 2021 model.