Job 21

Name_________________________________________________________ Date__________________ Instructor______________________________________________________ Period_________________

Project 7: Job 21—Service Automatic Transmission Components and Rebuild Subassemblies After completing this job, you will be able to service clutch packs, servos, accumulators, and other automatic transmission subassemblies.

Instructions As you read the job instructions, answer the questions and perform the tasks. Print your answers neatly and use complete sentences. Consult the proper service literature and ask your instructor for help as needed.

Warning Before performing this job, review all pertinent safety information in the text and discuss safety procedures with your instructor.

Procedures Note This job begins with a partially disassembled transmission. Refer to Job 20 for procedures for disassembling an automatic transmission. 1. Obtain an automatic transmission to be used in this job. Your instructor may direct you to perform this job on a shop transmission. 2. Gather the tools needed to perform the following job. Refer to the tools and materials list at the beginning of the project. 3. Obtain the proper replacement parts and compare them with the old parts to ensure the replacements are correct. 4. Soak all replacement friction discs, bands, and seals in clean transmission fluid of the proper type.

Service Clutch Packs 1. Use a clutch-pack spring compressor to compress the clutch-apply, piston-return spring(s), and then remove the snap ring holding the return spring retainer. Figure 21-1 shows a snap ring being removed from a drum. 2. Slowly release the spring compressor and remove the spring and retainer. 3. Remove the clutch-apply piston. 4. Remove the internal piston seals, Figure 21-2. 5. Clean all clutch piston parts and the interior of the clutch drum.

Copyright by Goodheart-Willcox Co., Inc.

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Project 7: Job 21—Service Automatic Transmission Components and Rebuild Subassemblies (continued) Figure 21-1. The snap ring that holds the piston return spring in place can be removed once the spring tension has been removed.

Figure 21-2. Internal piston seals can usually be removed with a small pick.

Note Some clutch drums and pistons contain air-bleed check balls. The check balls should be visible when you look straight down into their seat assembly, Figure 21-3. If you can see through the seat assembly, the ball is missing. Be sure that check balls are in place and can freely move. A drum or piston with a damaged or missing check ball is usually replaced. A few drums and pistons have replaceable check ball assemblies. 140


Name_________________________________________________________

Project 7: Job 21—(continued) Figure 21-3. Make sure that any drum air bleed check balls are in place and free to move. Most check balls rattle when the drum is shaken. Check ball seat assembly

6. Acquire new piston seals. Compare the replacement piston seals to the old seals. Are the new seals correct? Yes ___ No ___ 7. Install the new seals on the clutch piston (and clutch drum hub, if applicable).

Note Seals must be lubricated with the appropriate transmission fluid, special assembly lube, or petroleum jelly. 8. Install the piston in the drum being careful not to damage the seals. 9. Use the clutch-pack spring compressor to install the return spring and snap ring. 10. Install the clutches in the clutch drum, alternating friction discs and steel plates. Install any reaction plates at the top and bottom, as required. 11. Check the clutch pack clearance. Figure 21-4 shows clutch pack clearance being checked with a feeler gauge, which is the usual procedure. However, the clearance on some clutch packs is checked with a dial indicator. Refer to the manufacturer’s instructions. Specified clearance: ____________ Measured clearance: ____________ Is the clearance correct? Yes ___ No ___ If the clearance is incorrect, correct it by installing a different thickness spacer plate or snap ring. Remeasure the clearance. Is the clearance corrected? Yes ___ No ___ 12. Check the clutch pack by applying air pressure. The easiest way to do this is to place it over the mating stationary part and apply air through the feed hole. The clutch plates should move or, if the plates are not visible, a solid shock should be felt at the drum. There should be no air leakage. Does the clutch apply with air pressure? Yes ___ No ___ If Yes, go to step 13. If No, disassemble and recheck the piston seals and other drum components. 13. Repeat steps 1 through 12 for all clutch packs.


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Project 7: Job 21—Service Automatic Transmission Components and Rebuild Subassemblies (continued) Figure 21-4. Check and correct clutch pack clearance. Improper clearances will cause poor shift feel and early clutch failure. (DaimlerChrysler)

Selective snap ring

Measure clutch clearance Feeler gauge

Service Servos and Accumulators 1. Remove the snap ring or bolts securing the servo or accumulator cover. 2. Remove the servo or accumulator cover.

Note A special tool may be needed to depress the cover.

3. Disassemble the servo or accumulator. • Remove any snap rings or other retainers as necessary. • Remove the servo or accumulator piston(s) and return springs, Figure 21-5. • Carefully note the position of all parts for reassembly. 4. Remove the seals from the servo or accumulator piston(s). 5. Clean and inspect all servo or accumulator parts. Pay particular attention to the condition of the pistons and bores. Replace any of the following: • Cracked or scored pistons. • Broken springs. • Scored or damaged servo-apply pins, Figure 21-6. • Scored or damaged accumulator aligning pins. • Damaged snap rings or other retainers. • Parts with scored bores, Figure 21-7.

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Name_________________________________________________________

Project 7: Job 21—(continued) Figure 21-5. This servo is being removed from its bore.

Figure 21-6. Check the servo and accumulator pins for scoring. This servo pin is in good condition.

Note Some common transmission cases with scored servo or accumulator bores can be repaired with special sleeves. Smaller parts with damaged bores are usually replaced. 6. Acquire new seals. Compare the old and new seals. Are the new seals correct? Yes ___ No ___ 7. Install the new piston seals on the servo or accumulator piston(s). Copyright by Goodheart-Willcox Co., Inc.

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Project 7: Job 21—Service Automatic Transmission Components and Rebuild Subassemblies (continued) Figure 21-7. Check the servo and accumulator bores for damage or deposit buildup.

Note Seals must be lubricated with the appropriate transmission fluid, special assembly lube, or petroleum jelly. 8. Reassemble the servo or accumulator as necessary using new snap rings and retainers, when possible. 9. Install the servo or accumulator piston(s). 10. Install the servo or accumulator cover using the proper new O-ring or gasket. 11. Repeat steps 1 through 10 for all servos and accumulators.

Service Other Components 1. Clean, inspect, and rebuild other subassemblies in the transmission according to the manufacturer’s instructions. The following steps are general guidelines. 2. Valve body. Ensure that all valves and springs are correctly installed and that all fasteners are correctly tightened. Check that solenoids are correctly installed. Clean or replace solenoid screens and any other screens. Make a final check to ensure that the valves freely move, Figure 21-8. 3. Oil pump. Replace worn gears and the front pump bushing. Lightly oil the pump before reassembling. Tighten the pump fasteners to the exact torque following the proper sequence. If applicable, install a new pump seal. 4. Seal rings. Always install new seal rings. Make sure the rings are correct and that the proper fit exists between the rings, ring grooves, and ring bore. Do not expand the rings any more than necessary to install them into the groove.

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Name_________________________________________________________

Project 7: Job 21—(continued) Figure 21-8. After cleaning the valve body, make sure that the valves move freely in their bores. If any valve is sticking, remove it and determine the cause. Also, remove and inspect valves if there is any reason to believe that a valve may have been installed incorrectly or if a shift improvement package is being installed.

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5. Planetary gears. Replace worn gears, bushings, thrust washers, and needle bearings. Sometimes, it is possible to replace one gear of a planetary gearset instead of replacing the entire gearset. Consult your instructor to determine whether individual planetary gears can be replaced. 6. Bushings. Carefully press out worn bushings and press in new bushings using a hydraulic press and the proper bushing drivers.

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Job Wrap-Up 1. Clean the work area and return any equipment to storage. 2. Did you encounter any problems during this procedure? Yes ___ No ___ If Yes, describe the problems:_______________________________________________________ What did you do to correct the problems?_ ____________________________________________ 3. Have your instructor check your work and sign this job sheet.


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Project 7: Job 21—Service Automatic Transmission Components and Rebuild Subassemblies (continued)

Performance Evaluation—Instructor Use Only Did the student complete the job in the time allotted? Yes ___ No ___ If No, which steps were not completed? ____________________ How would you rate this student’s overall performance on this job?_________________________ 1–Excellent, 2–Good, 3–Satisfactory, 4–Unsatisfactory, 5–Poor Comments:___________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ INSTRUCTOR’S SIGNATURE_ _________________________________________________

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