A Transfer Case is a fundamental part of the 4-wheel drive system on your Chevy Silverado or GMC Sierra 2500HD/3500HD. The LLY Duramax trucks came equipped from the factory with either a Magna Powerstrain MP1625 transfer case or MP1626 transfer case (MP1625HD / MP1626HD). The LML Duramax Transfer Case mounts to the back of the transmission and is what the front and rear drive shafts connect to. Contained inside the transfer case is a set of gears and chains that are engaged or disengaged depending on the drive mode selected. The transfer case in a 4-wheel drive system is responsible for transferring power to both the front and rear axles. 4-wheel high will maintain the same gear ratio as 2-wheel drive and is for high-speed situations such as driving on dirt or snow-covered roads. 4-wheel high is used in high-speed settings such as dirt or snow, whereas 4-wheel low is used in low-speed settings like steep rocky hills where maximum wheel torque is required.

When you shift the Transfer Case into 4-wheel drive, it locks the front and rear axles together so that they spin at the same speed. The Transfer Case is designed to be used in off-road or low-traction situations and is not recommended to be used on dry pavement where wheel slip is not possible. When engaged in 4-wheel drive the transfercase and drivetrain need some wheel slip to prevent binding or damage. A Transfer Case typically does not require internal upgrades or modification unless the vehicle will be used for extreme off-roading or racing applications. External upgrades such as transfer case braces are offered for certain applications that add structural rigidity to prevent damage from high torque loads and twisting. Shop XDP's large selection of Duramax LML Transfer Case products from the top brands such as Zumbrota Drivetrain, Merchant Automotive, PPE, Sun Coast Converters, Dorman, and more.