SERVICE MANUAL UPDATE SEC. 7A A/T INTERMEDIATE SERVO INFO

Subject: INTERMEDIATE SERVO

Model and Year: 1991 GEO STORM WITH KF400 3-SPEED AUTOMATIC TRANSMISSION

This bulletin has been written as an addition to Section 7A-1 of the 1991 GEO Storm Service Manual and covers on-vehicle service procedures for the intermediate servo on base model GEO Storm vehicles equipped with the KF400 3-speed automatic transaxle.

Figure 1 Servo Components

On-Vehicle Service

Intermediate Servo Figures 1 through 4

Remove or Disconnect

Tool Required:

J 35278 Servo Piston Compressor

1. Negative (-) battery cable. 2. Positive (+) battery cable. 3. One bolt, one nut and battery hold down bracket from battery 4. Battery from vehicle. 5. Transaxle kickdown solenoid electrical connector from transaxle kickdown solenoid harness. 6. Transaxle kickdown solenoid harness from retaining clip.

o Raise and suitably support vehicle. Refer to General Information (Section 0A).

7. Five screws and left splash shield from vehicle.

o Place a drain pan or suitable container under the transaxle fluid pan.

8. Transaxle fluid pan drain plug from transaxle fluid pan and drain transaxle fluid. 9. Left drive axle from vehicle. Refer to Drive Axle (Section 4D) in the 1991 GEO Storm Service Manual (ST371-91). 10. Kickdown solenoid from transaxle by unscrewing counterclockwise. 11. Vacuum hose from vacuum modulator. 12. Vacuum modulator and diaphragm rod from transaxle by unscrewing vacuum modulator counter- clockwise. 13. Sixteen bolts and transaxle fluid pan and gasket from transaxle. 14. Ten retaining bolts and valve body assembly from transaxle.

Install a J 35278 servo piston compressor to the transaxle and tighten the J 35278 servo piston compressor bolt until the servo cover snap ring can be removed (Figure 2).

Figure 2 Removing Servo Cover Snap Ring

15. Servo cover snap ring from servo bore.

Slowly loosen the J 35278 servo piston compressor bolt until the J 35278 servo piston compressor can be removed.

16. The J 35278 servo piston compressor.

IMPORTANT: Use caution not to lose the servo piston strut engaged at the intermediate brake band. Remove it simultaneously with the servo cover, servo piston and servo piston spring (Figure 3).

Figure 3 Servo Piston Strut

17. Servo cover, servo piston and servo piston spring from servo bore while simultaneously removing the servo piston strut from the intermediate brake band. 18. Servo piston spring from servo piston. 19. Servo piston from servo cover. 20. One seal from servo cover. 21. Two seals from servo piston.

Clean

o All parts with clean solvent and dry thoroughly. o Transaxle fluid pan mating surfaces.

Inspect

o Servo bore for minor nicks, scars or other damage. If minor nicks or scars are found, remove with ultra-fine emery cloth. If deep nicks or scars are found, replace the transaxle case as necessary.

o All servo components for damage. Replace as necessary.

o Vacuum modulator 0-ring for cuts or damage. Replace as necessary.

o Kickdown solenoid 0-ring for cuts or damage. Replace as necessary.

Install or Connect

Tools Required:

J 36850 Transjel (R) Transmission Assembly Lubricant J 35278 Servo Piston Compressor

1. Two new seals on the servo piston. 2. One new seal on the servo cover. o Liberally apply J 36850 Transjel (R) transmission assembly lubricant to the new seals on the servo piston and servo cover.

3. Servo piston into the servo cover. 4. Servo piston spring onto the servo piston. 5. Servo piston spring, servo piston and servo cover into the servo bore while simultaneously engaging the servo piston strut at the intermediate brake band (Figure 4).

Figure 4 installing Servo Spring, Servo Piston and Servo Cover

6. The J 35278 servo piston compressor to the transaxle and tighten the J 35278 servo piston compressor bolt until the servo cover snap ring can be installed. 7. Servo cover snap ring into the servo bore.

o Slowly loosen the J 35278 servo piston compressor bolt until the J35278 servo piston compressor can be removed from the transaxle. o Remove the J35278 servo piston compressor from the transaxle.

8. Valve body assembly to the transaxle aligning the manual valve with the shift lever arm; secure with ten retaining bolts.

Tighten

o Valve body assembly retaining bolts to 10 N.m. (89 lbs.in.),

9. Transaxle fluid pan with new gasket to transaxle; secure with sixteen bolts.

Tighten

o Transaxle fluid pan bolts to 7 N.m. (62 lbs. in

10. Vacuum modulator with diaphragm rod into transaxle by screwing the vacuum modulator into the transaxle clockwise. 11. Vacuum hose to vacuum modulator. 12. Kickdown solenoid into transaxle by screwing in clockwise. 13. Left drive axle into vehicle. Refer to Drive Axle (Section 4D) in the 1991 GEO Storm Service Manual (ST371-91). 14. Transaxle fluid pan drain plug into transaxle fluid pan.

Tighten

o Transaxle fluid pan drain plug to 28 N.m. (20 lbs. ft.). o Remove drain pan from under transaxle fluid pan.

15. Left splash shield onto vehicle; secure with five screws.

o Lower vehicle

16. Transaxle kickdown solenoid harness into retaining clip. 17. Transaxle kickdown solenoid electrical connector to transaxle kickdown solenoid harness. 18. Battery into vehicle. 19. Battery hold down bracket onto battery; secure with one bolt and one nut.

Tighten

o Battery hold down bracket bolt 5 N.m. (44 lbs. in.). o Battery hold down bracket nut to 8 N.m. (62 lbs. in.).

20. Positive (+) battery cable.

Tighten

o Positive (+) battery cable-to-positive (+) battery terminal retainer to 15 N.m. (11 lbs. ft.).

21. Negative (-) battery cable.

Tighten

o Negative (-) battery cable-to-negative (-) battery terminal retainer to 15 N.m. (11 lbs. ft.).

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.