8HP70, 8HP75

Symptoms:

• "D" Clutch burned
• Reverse slip
• No Reverse
• Gear ratio codes
• Slipping gears

Cause:
The weak OE "D" clutch backing plate allows major flex that causes irregular clutch wear and burning.

Correction:
Eliminate the flexing that leads to comebacks by installing the thicker, stiffer Sonnax heavy duty "D" clutch backing plate.

The "D" clutch in ZF8HP55, ZF8HP70 and ZF8HP75 transmissions has a thin, stamped OE backing plate that allows flexing and bowing (coning) of the clutch pack. This wears the clutches unevenly, generating and concentrating extra heat which leads to clutch burnup. The result is slipping or no 4th through 8th and Reverse Gears, as well as ratio codes. Sonnax heavy duty "D" clutch backing plate 123399S is designed to prevent flexing when the clutch is applied, eliminating a leading cause of "D" clutch failure.

• 2X thicker than weak, stamped OE backing plate for significantly improved protection against burnup
• Easy to install, no special tools or machining required
• Prevents comebacks by installing in units that have not yet failed

Specs:

• Material: Billet Steel