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Technical Service Information
ZF4HP22
ERRATIC OR NO UPSHIFTS
COMPLAINT: Vehicles equipped with the ZF4HP22 transmission may come to the shop with no
upshift or complaints of erratic shifting.
CAUSE: During an internal inspection, close examination of the (F) clutch cylinder that
bolts into the case will be necessary. Abnormal ring groove wear on the drum where
the governor rides will cause the loss of governor pressure. With a new ring installed
on the drum, side clearance should be .003"-.006" in. (SEE FIGURE 1).
CORRECTION: A new (F) clutch cylinder must be installed if any wear or damage is found. New
sealing rings must also be installed. Rubber sealing rings will work, but steel rings are
the preferred choice. The part number for the (F) clutch cylinder is 24-23-1217-088.
.003"-.006" SIDE CLEARANCE
GROOVE WORN HERE
Figure 1
92-13
AUTOMATIC TRANSMISSION SERVICE GROUP Page 1 of 1