Vehicles with ZF8HP55 and ZF8HP75 transmissions utilize an "E" hub that is made from weak, cast A380 aluminum. This material is no match for the high torque generated in these applications. The lock splines of the hub are prone to shearing or breaking, resulting in failsafe, ratio codes and loss of movement. In addition, the steel clutch plates dig into the splines on the drum, causing the plates to hang up and burn. This can happen in as few as 20,000 miles. heavy duty "E" clutch hub 35572-48T is crafted from forged 4000-series aluminum, the same material used for high performance engine pistons. The billet hub features a far superior yield strength versus the OE hub, so you can rest easy knowing it will stand the test of time - no more worrying about comebacks due to a failed OE hub. * High-strength, forged hub eliminates spline failure* Improved material significantly increases "E" clutch durability