What is the maximum towing capacity of 2006 GMC 2500 HD pickup with 6.6L duramax diesel engine and6 speed Allison transmission?

The maximum towing capacity of a 2006 GMC Sierra 2500HD with the 6.6L Duramax diesel and 6-speed Allison transmission varied depending on configuration (cab style, bed length, axle ratio, and options). There's no single definitive answer.

To find the exact towing capacity for a *specific* truck, you need to look at the sticker located on the driver's side doorjamb. This sticker will show the GVWR (Gross Vehicle Weight Rating), GAWR (Gross Axle Weight Rating - front and rear), and the truck's specific towing capacity.