it is the front tank correct?I pulled the tank on a 2017 2500 Duramax not to long ago & was pretty easy, The exhaust is on the passenger side on both diesel & gas trucks.
Remove the 3 screws on the filler neck mount, Remove plastic shield if equipped, Disconnect the lines, Remove the straps....Shift the tank away from the frame rail & disconnect the filler hose, Lower the tank 'til you can unplug the electrical connector.