A/T - Harsh Closed Throttle 4-3 Downshift

89AMCjeep05

Models

1988-89 BB Vehicles Built Before 02-20-89 With ZF Automatic Transaxle


Subject

Harsh 4-3 Closed Throttle Downshift Excessive Closed Throttle Harshness In Third Gear


Index

TRANSMISSION


Date

August 7, 1989


No.

21-59-89

(C21-14-9)

P-2975
BODY CODE LEGEND

BB - EAGLE PREMIER


SYMPTOM/CONDITION

Some 1988-89 vehicles equipped with the ZF transaxle may exhibit one or both of the following conditions.

- Harsh 4-3 closed throttle down shift on vehicles built before 01-13-89 with ZF Automatic Transaxles built before transaxle sequence number 72018.

- Tip out harshness and excessive engine braking during closed throttle deceleration in third gear on vehicles built before 02-20-89 (MDH 02-20-XX).

DIAGNOSIS

Road test vehicle observing the transmission shift quality. Early shifts, slipping between shifts, delayed shifts and sensitive downshifts indicate an incorrectly adjusted throttle cable. Adjust the transmission throttle valve cable as outlined on Page 21-23 in the 1989 Premier Service Manual (81-270-9040).

If the shift quality is found to be normal EXCEPT for a harsh 4-3 closed throttle downshift and/or tip out harshness and excessive engine braking during closed throttle deceleration in third gear, perform the following repair procedure as required.

PARTS REQUIRED

1 Valve Body Assembly P/N 04549231
1 Gasket (Oil Pan) P/N 83504677
1 Engine Control Unit P/N 05234642
REPAIR PROCEDURE

This repair involves replacement of the valve body assembly and/or engine control unit.

1. Check the vehicle build date. If the MDH is before 01-13-XX, perform step 2 through step 28. If the built MDH is 01-13-XX to 02-20-XX, perform step 2 through 6.

2. Raise hood and disconnect the negative battery cable.

3. Remove the ECU mounting nuts and ground strap, (the ECU is located under the instrument panel on the passenger side of the vehicle) remove the ECU from the vehicle. (Figure 1)
4. Connect the harness connector to the new ECU.

5. Position the ECU over the mounting studs, install the ground strap and tighten the mounting nuts.

6. Connect the negative battery cable.

7. Shift the transmission into manual first gear range.

8. Raise the hood, remove engine cover. Prop throttle control linkage to the wide open position.


NOTE: PROPPING THE THROTTLE IN THE WIDE OPEN POSITION WILL PREVENT JAMMING THE THROTTLE CAM AND PISTON DURING INSTALLATION OF NEW VALVE BODY.

Figure 1:

Figure 2:

9. Raise vehicle and remove splash shield.

10. Loosen the fill tube to oil pan attaching nut and drain the transmission fluid. After the fluid has drained disconnect the fill tube from the oil pan.

11. Remove the four (4) oil pan attaching nuts and clamps. Remove the oil pan.

12. Remove the eleven (11) valve body attaching bolts, Figure 2. Remove the valve body.

Figure 3:

13. Inspect the selector lever position to ensure it remained in the manual first gear range (Figure 3).

NOTE: WHEN THE SELECTOR LEVER IS ROTATED COUNTERCLOCKWISE TO THE LAST DETENT POSITION, IT WILL BE IN THE MANUAL FIRST GEAR RANGE.

Figure 4:

14. Push the valve body manual valve all the way in until it bottoms, this is the manual first gear position (Figure 4).

Figure 3:

15. Align and install the new valve body on the case.

16. Install and tighten the eleven (11) valve body bolts to the torque specification in Figure 2. Be sure the correct length bolt is installed at each location shown in Figure 2.
17. Clean the oil pan and pan gasket surface on the transmission case.

18. Install the new pan gasket on the oil pan, position the oil pan on the case.

19. Install the pan retaining clamps and tighten the clamp nuts to 6 N-m (54 in.lbs) torque.

20. Clean the fill tube nut threads. Apply thread sealer P/N 83100065 to the first two (2) threads of the oil pan fitting.

21. Connect fill tube nut to oil pan fitting and tighten nut to 100 N-m (74 ft.lbs).

22. Install splash shield and lower vehicle.

23. Return the throttle to the curb idle position.

24. Adjust the transmission throttle valve cable as outlined on Page 21-23 in the 1989 Premier Service Manual (81-270-9040). Install engine cover.

25. Remove the transmission dipstick and add three (3) quarts of MERCON transmission fluid (P/N 82200922).

26. Set parking brake, start engine, shift transmission through all ranges and return to the PARK position.

27. Let the engine idle until the engine cooling fan has cycled three (3) times.

28. Check the fluid level on the side of the dipstick marked HOT. The level is correct if it is within the crosshatch area between the ADD and FULL marks on the dipstick. Adjust fluid level as required only after the transmission is at operating temperature.


CAUTION: IT REQUIRES ONLY 1/2 PINT (0.25 LITER) OF FLUID TO RAISE THE LEVEL FROM THE ADD TO FULL LINE. DO NOT OVERFILL.

POLICY: Reimbursable within the provision of the warranty.


TIME ALLOWANCE:
Labor Operation No. 08-15-62-90
. . . . . . . . . . . 0.3 Hrs.
ENGINE CONTROL UNIT-REPLACE

21-95-01-93 . . . . . . . . . . . . 1.4 Hrs.
ENGINE CONTROL UNIT AND VALVE BODY-REPLACE


FAILURE CODE: 58 - Internal Defect