Standard issue on the 2006 Dodge Ram Mega Cab 1500 and 2500 is a 5.7-liter Hemi V8 linked to a five-speed automatic transmission. This V8 makes 345 horsepower and 375 lb.-ft. of torque. Available as an option on the 2500 and standard on the 3500 is a 5.9-liter Cummins turbodiesel with 325 horsepower and a stump-pulling 610 lb.-ft. of torque. The Cummins is available with either a six-speed manual or six-speed automatic transmission.