A/T - ZF 4HP-22 Clutch A (Foward) Failure

TSB 88 - 43 (Sept)

SUBJECT: ZF 4HP-22

PROBLEM: "Clutch A" Failure

CAUSE: May have excessive wear inside stator shaft




If "Clutch A" is burned, check inside the stator shaft for grooves where the sealing rings contact the bore. (See Figure 1)




Tow oil control rings for "Clutch A" are located on the input shaft. (See Figure 2)

These rings must seal against the inside diameter of the stator shaft.

If the inside of the stator shaft becomes ring grooved where the "Clutch A" oil rings seal, a leak in "Clutch A" Pressure will occur, resulting in no forward, or slippage in all forward ranges.