Engines and modifications Sierra 3500HD V (GMTT1XX) Double Cab Long Bed

6.6 V8 (401 Hp) SRW Automatic

6.6 V8 (401 Hp) DRW Automatic

6.6 V8 (401 Hp) 4WD SRW Automatic

6.6 V8 (401 Hp) 4WD DRW Automatic

6.6 Duramax TD V8 (445 Hp) SRW Automatic

6.6 Duramax TD V8 (445 Hp) DRW Automatic

6.6 Duramax TD V8 (445 Hp) 4WD SRW Automatic

6.6 Duramax TD V8 (445 Hp) 4WD DRW Automatic