There are a few different engines in the Duramax line, but the most popular and sought-after is the 6.6L turbo diesel. This engine was first introduced in 2001 and has been constantly updated and improved over the years. It's now in its third generation and offers incredible power, torque, and efficiency. Whether you're looking for a workhorse to tow your toys or just wanting a reliable daily driver, the Duramax 6.6L is the perfect choice.