Allison® 1000 6-speed automatic transmission

With over a decade on the job, the legendary heavy-duty Allison® 6-speed transmission harnesses the power of the available Duramax® 6.6L Turbo-Diesel V8 engine.


  • Driver Shift Control (DSC), which allows the driver to manually select upshifts and downshifts with buttons on the column shifter
  • Tow/Haul mode reduces shift cycling for better control and improved cooling when towing or hauling heavy loads
  • Automatic Grade Braking uses the engine and transmission to slow the vehicle on downhill grades and help reduce brake wear (operates in Tow/Haul mode)

The durable Allison 6-speed puts you in control of all the intensity Duramax throws out. It requires the available Duramax 6.6L Turbo-Diesel V8 engine.