BMW 8hp7X Billet 7075 Aluminum D Drum

The ZF8HP70 transmission is known for problems with its OE “D” clutch hubs, which are made from weak cast A383 aluminum. Over time, the steel cores of the clutch plates wear down the aluminum splines on the hub, leading to failure. This wear can begin after just a few thousand miles and often results in burnt clutches. Additionally, the backing plate may flex, causing uneven wear on the friction material. These design flaws contribute to a high failure rate—sometimes even within the OE warranty period—and can result in loss of 4th through 8th gears and Reverse. The Deka "D" clutch hub (part number 35570-70K) solves these issues with a rugged, two-piece riveted assembly. It features a hardened steel hub that prevents spline wear from the steel clutch plates and comes pre-fitted with a new bushing, ready for drop-in installation. Key Features: Heavy-duty, two-piece riveted construction Steel hub resists spline wear from steel clutch plates Includes pre-installed bushing Common Symptoms: Burned “D” clutch No Reverse No 4th–8th gears Root Cause:Premature spline wear on the factory aluminum “D” clutch hub from repeated contact with steel clutch plates. Solution:Replace the OE hub with the Deka steel “D” clutch hub to eliminate wear and extend clutch life. Important Installation Note:To avoid damaging the Deka hub during snap ring removal, always use appropriate drum protection tools such as the Adapt-A-Case T-3500AC or Automatic Choice 8HP45.TOOL01.