A/T - ZF4HP22 Clutch A (Foward) Failure
DATE: June 1991TRANSMISSION: ZF4HP22
BULLETIN: # 056
SUBJECT: "A" Clutch Failure
APPLICATION: ZF
ZF4H P-22
"A" Clutch Failure
The stator support has been updated with a checkball capsule to help eliminate premature "A" clutch failure. If you want to add a check ball capsule to the early type you'll need a 15/64" drill, a 23/64" drill, a 1/4" checkball capsule, a 9/32" punch, a 3/8" cup plug and some red LOCTITE.
1. Drill a 15/64" hole into the "A" clutch passage. Start in the back of the support and drill all the way so the drill comes out the front. (Figure 1)
2. Turn the support over and enlarge the front hole to 23/64". Drill through the front hole and make a seat for the check ball capsule on the inside of the rear hole, but don't go all the way through. (Figure 2)
3. Now put some red LOCTITE on the outside of the check ball capsule and drive it in through the 23/64" hole in front (figure 3). Figure 4 shows the capsule in place.
4. Now drive the cup plug into the pump to plug the 23/64" hole. (Figure 5)
FOR ADDITIONAL INFORMATION:
Technical Bulletin # 9001004 January 1990
BULLETIN RECAP
Parts List
^ 1/4" check ball capsule
^ GM part # 8633748
^ 3/8" cup plug
^ Red LOCTITE
Tools Needed
^ 15/64 drill
^ 23/64 drill
^ 9/32 punch