6-Speed Aisin HD Automatic
Transmission, 6-speed automatic, heavy-duty, electronically controlled with overdrive and tow/haul mode. Includes Cruise Grade Braking and Powertrain Grade Braking (Requires (L96) Vortec 6.0L V8 SFI engine or (LC8) 6.0L V8 SFI Gaseous CNG (Compressed Natural Gas) engine.) (Requires (L96) Vortec 6.0L V8 SFI engine or (LC8) 6.0L V8 SFI Gaseous engine.)
Cooling, auxiliary external transmission oil cooler