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


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


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

ZF8HP55, ZF8HP70, ZF8HP75

Heavy Duty "D" Clutch Backing Plate
Part No. 35570-75

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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 35570-75 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
  • Prevent comebacks by installing in units that have not yet failed
  • Material: Billet Steel
  • ZF8HP55, ZF8HP70, ZF8HP75 Heavy Duty "D" Clutch Backing Plate 35570-75