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


The weak OE "A" 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 "A" clutch backing plate.

ZF8HP55, ZF8HP70, ZF8HP75

Heavy Duty "A" Clutch Backing Plate
Part No. 35577-70

Find a Distributor

The "A" 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 1st/2nd, 7th/8th and Reverse Gears and ratio codes. Sonnax heavy duty “A” clutch backing plate 35577-70 is designed to prevent flexing when the clutch is applied, eliminating the leading cause of "A" 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 "A" Clutch Backing Plate 35577-70


How to Prevent ZF8, 845RE, 850RE "A" Clutch Failure