OBJECTIVES

Automatic Transmissions and Transaxles, Fourth EditionBy Tom Birch and Chuck Rockwood

© 2010 Pearson Higher Education, Inc.Pearson Prentice Hall - Upper Saddle River, NJ 07458

OBJECTIVES

After studying Chapter 17, the reader should be able to:

1. Properly perform the standard overhaul procedures.

2. Describe the methods used to clean an automatic transmission and its components.

3. Inspect, remove, and replace bushings and thrust washers.

4. Disassemble, inspect, and assemble a clutch assembly.

5. Remove and replace the various seals used in an automatic transmission.

6. Complete the ASE tasks related to inspection and replacement of bushings, thrust washers, friction material, and seals.



INTRODUCTION

• A transmission overhaul is a complete reconditioning that will bring the transmission back to like-new vehicle operation.

• This requires that worn parts be replaced so the original clearances are restored. An overhaul should include the following:1. complete disassembly and cleaning2. careful inspection of each part and component3. replacement of any worn or damaged hard parts4. replacement of any worn or damaged bushings or thrust washers5. replacement of all clutch friction plates6. replacement of any worn or damaged clutch steel plates7. replacement of the intermediate band and any other worn or damaged bands8. replacement of all internal and external seals and gaskets9. disassembling, cleaning, and reassembling the valve body10.rebuilding or replacing the torque converter11.adjusting all clearances to the manufacturer’s specifications



COMPONENT CLEANING

• The internal parts, case, and extension housing are cleaned after disassembly.

• Some technicians set major components aside to be thoroughly cleaned as they are disassembled and serviced.

• Cleaning methods that are commonly used are hot spray wash, water solution wash, cold dip, and solvent wash.

FIGURE 17-1 Expensive transmission failures can be caused by debris in the cooler. (Courtesy of Sonnax)



COMPONENT CLEANING

FIGURE 17-2 A spray wash cabinet contains a pump that sprays heated cleaning solution as the parts basket is rotated. (Courtesy of ATEC Trans-Tool and Cleaning Systems)



COMPONENT CLEANING

FIGURE 17-3 This parts washer contains a pump that delivers the heated cleaning solution to a cleaning brush and flexible outlet. (Courtesy of ATEC Trans-Tool and Cleaning Systems)



BUSHING, BEARING, AND THRUST WASHER SERVICE• Bushings and bearings are used to support rotating shafts.• Thrust washers are used to separate rotating parts from

each other or from stationary parts

FIGURE 17-4 Parts 8657, 730, 677, 5443, 670, 2279, 6749, and 655 are thrust washers. The nine replaceable bushings for this transmission are not shown. (Courtesy of Slauson Transmission Parts,www.slauson.com)



BUSHING, BEARING, AND THRUST WASHER SERVICE

FIGURE 17-5 The inner and outer bearing journal of this carrier show severe wear (a). The nylon thrust washer shows that it is deformed and nearly melted (b). Both failed because of poor lubrication and overheating.




FIGURE 17-6 A thrust bearing can have a specially shaped race at each side or use the transmission component for the race. The race can be part of the bearing or separate. Correct installation is essential.




FIGURE 17-7 These bushings have failed from embedded debris (a), abrasion (b), wiping and overheating (c), and spin out (d). (Courtesy of Sonnax)



TECH TIP

• Most manufacturers do not publish clearance or size specifications for bushings; a few publish thrust washer thickness specifications.

• If you want to measure bushing clearance to gain experience, use the rule of thumb that anything over 0.006 in. (0.152 mm) is excessive.

FIGURE 17-8 A quick and simple check for bushing clearance is to place a strip of paper between the converter hub and bushing. The paper is about 0.003 in. thick, so you should be able to remove it with a slight drag.



BUSHING, BEARING, AND THRUST WASHER SERVICE• Bushing Removal

– Several methods can be used to remove a bushing.

– Always check and note the position of any grooves or oil passages.

FIGURE 17-9 Special tool SP-3629 is being used to drive the bushing out of the clutch housing (top). Note

that special tool SP-5511 for the bushing installation has a lip that prevents installing the bushing too deep

(bottom). (Courtesy of Chrysler Corporation)




FIGURE 17-10 A slide hammer (a) with a remover adapter (b) can be used to pull a bushing from its bore. (Courtesy of ATEC Trans-Tool and Cleaning Systems)




FIGURE 17-11 A chisel is being used to cut a groove through the bushing so it can be collapsed. Be careful to not damage the bushing bore.



TECH TIP

• Very small bushings are usually removed by cutting threads in them so a slide hammer can be threaded into the bushing.

FIGURE 17-12 The special toolset threads into the bushing; turning the nut at the top will pull the bushing

out. (Courtesy of Chrysler Corporation)



TECH TIP

• Technicians are very resourceful; they design special tools that may be better than those designed by the vehicle manufacturer.

FIGURE 17-13 This band-adjusting screw from a C6 has a cutting groove in the threads, and the nut has

been welded into place. With the use of an air wrench, it can cut threads into the bushing at the front of a TH 350 mainshaft; it will bottom in the bore and force the

bushing out.



BUSHING, BEARING, AND THRUST WASHER SERVICE• Bushing Installation

– A bushing installer should be used to push the new bushing into its bore to prevent damaging it or the bore.

– This is often the same tool that was used to remove the bushing.

FIGURE 17-14 Bushing drivers are used to drive bushings into the proper position.

(Courtesy of Chrysler Corporation)




FIGURE 17-15 Some bushings are locked into position by staking them using a blunt punch. Any raised metal is then scraped off. (Courtesy of Chrysler Corporation)



BUSHING, BEARING, AND THRUST WASHER SERVICE• Tapered Roller Bearing

Service– Some transaxles use tapered

roller bearings.

FIGURE 17-16 The cup, rollers, and cone of a tapered roller bearing are machined at an angle as shown. This allows them to resist a thrust in the direction indicated by the P arrows. The bearing is preloaded in this direction; any clearance at the sides of the bearing (C arrows) is called freeplay.




FIGURE 17-17 Special tools are often required to remove tapered roller bearings (a) and the cups (b). (Courtesy of Chrysler Corporation)




FIGURE 17-18 When roller bearings are to be reused, they should be marked or tagged so they can be put back in the same position with the same races/cups.

FIGURE 17-19 This bearing set is adjusted with a selective shim placed under the bearing cup; a thicker shim will reduce the clearance or increase the preload on the bearing. (Courtesy of Chrysler Corporation)




FIGURE 17-20 If this bearing set is adjusted correctly, it will take 2.2 inch-pounds (in-lb) (0.2 N-m) of torque to rotate the differential.



FRICTION MATERIAL SERVICE

• There are three opinions concerning replacement of automatic transmission friction material (lined plates, unlined plates, and bands) during an overhaul:– Replace all friction material as a standard practice.– Replace all lined plates and the unlined plates and bands

as needed.– Replace only the worn or damaged items.



TECH TIP

• If the lining appears to be delaminating or coming loose from the core, peel the lining off and look for rust on the steel core.

FIGURE 17-21 The lining is lifted off of this friction plate. It shows rust and corrosion that are evidence of water damage. (Courtesy of Raybestos)




• Lined Plate Service– If lined plates are to be reused, they should be carefully

inspected.– The requirements for reuse of a lined plate are as follows:

• The lining wear is minimal.

• There must be no breaking up or pock marks in the lining.

• There must be no metal particles embedded in the lining.

• The lining must not come apart when scraped with a coin, fingernail, or knife blade.

• The lining must not have a glazed, shiny appearance.

• The lining material must not be severely discolored.

• The plate must be flat.

• The splined area must be flat and even.




FIGURE 17-22 The lining can be easily scraped from the plate; this disc should not be reused.




• Steel Plate Service– Unlined steel plates are often reused. – They must be carefully inspected before reuse:

• The plate must be flat (except for wave or Belleville plates).

• There must be no sign of surface irregularities.

• The splined area must be flat and even.

• Slightly burned plates must be replaced or reconditioned.




• Band Service– If a band is to be reused, it should be checked to ensure

that:• the lining material is sound with no breaking up or pock marks

• the lining material does not come apart when scraped with a thumbnail or knife blade

• the lining thickness is almost the same as that of a new band

• the lining material is not badly discolored or does not appear burned

• there are no metal particles embedded in the friction material

• the end lugs appear tight and unworn




FIGURE 17-23 A profilimeter shows the profile of a steel plate (a); one micro-inch (1μ in) equals 0.000001 in. The actual shape of the surface roughness can vary (b), but both of these plates have the same surface roughness. (Courtesy of Raybestos)



TECH TIP

FIGURE 17-24 This tool can rotate a basket of steel plates and special media to cause a tumbling action that cleans and retextures the surface. (Courtesy of ATEC Trans-Tool and Cleaning Systems)




FIGURE 17-25 Two badly worn drums (a and b); both are scored and polished, and (b) shows burn marks. Four faulty bands: (c and d) two broken bands; (e) burned and flaking lining; and f is worn out.




FIGURE 17-25 (CONTINUED) Two badly worn drums (a and b); both are scored and polished, and (b) shows burn marks. Four faulty bands: (c and d) two broken bands; (e) burned and flaking lining; and f is worn out.




• New Friction Material Preparation– New friction material must never be used in a dry,

unlubricated condition. – Dry lining acts like an insulator. – It easily overheats and burns from the heat of friction

created during the first shift. – The lined material should be soaked in ATF for at least 20

minutes before installation; some shops soak the plates overnight.



TECH TIP

• Some transmissions use a drum made from a steel stamping rather than from a forging or a casting.

• These units should be checked for dishing by laying a straightedge along the drum surface

FIGURE 17-26 Stamped steel drums should be checked for dishing. There should be no clearance between the drum and the straightedge.



TECH TIP

• If the drum surface is smooth but polished, it can be sanded to produce a better finish.

• If a paper-lined band is used, use 150- to 160-grit sandpaper, and sand in a direction that goes around the drum

FIGURE 17-27 If a drum surface is polished, it can be sanded to roughen the surface. If a paper band is used, sand around the drum using 120-or 180-grit emery cloth or sandpaper. If a fabric band is used, sand in a front-to-back direction using 40- to 60-grit sandpaper.



INTERNAL SEAL SERVICE

• An important part of a transmission overhaul is the correct replacement of the internal seals.

FIGURE 17-28 Four styles of Teflon rings; the uncut, continuous ring requires special tools for installation.

The other styles are placed into the groove with overlapping ends positioned properly.




• Fitting Rubber Seals– Always check a seal in the

bore where it will operate. – In most cases, this takes very

little time. An O-ring seal (round or square-cut) is first checked by placing it in the bore by itself.

FIGURE 17-29 Each of these accumulator pistons has an O-ring seal that should have a snug fit in the bore. (Courtesy of Toyota Motor Sales USA, Inc.)



TECH TIP

• The seals can be checked for size by placing them one at a time in their operating position.

• Start with the seal that is easiest to remove and replace.

• Place one seal on the piston, lubricate it with ATF, and work it into the bore.

• Now stroke the piston, and feel for drag

FIGURE 17-30 The inner piston seal is installed, and the piston is slid into the bore to check its fit (step 1).The piston is removed, and the fit of the outer seal is checked (step 2).Then both seals are installed and lubricated, and the piston is installed for the final time (step 3).



TECH TIP

FIGURE 17-30 (CONTINUED) The inner piston seal is installed, and the piston is slid into the bore to check its fit (step 1).The piston is removed, and the fit of the outer seal is checked (step 2).Then both seals are installed and lubricated, and the piston is installed for the final time (step 3).




• Installing Pistons with Lip Seals– The clutch piston should be inspected before seal installation

FIGURE 17-31 A piston should be checked for any signs of damage, porosity, nicks at the seal groove, and a missing or stuck check ball.



TECH TIP

• Wax lubricant, often called door ease, is commonly used for vehicle door or hood striker plates.

• Smearing a film of wax lubricant around the seal and at the edge of the bore is often just enough lubricant to allow the seal to slip into the bore.

FIGURE 17-32 Piston and seal installation can be made easier if a film of wax lubricant is smeared around the seals and seal area.



TECH TIP

• Seal installation tools are commercially available or you can make one by rounding the edges of a feeler gauge that is 0.005 to 0.010 in. (0.15 to 0.25 mm) or squeezing a bent, thin piece of piano wire into the end of a small tubing.

FIGURE 17-33 When the piston is installed, the seal tends to catch on the upper end of the piston bore (a,arrow). A thin feeler gauge or shop-made seal installing tool can coax the seal past this edge (b).



TECH TIP

• Seal guides are available for some clutch units. • These are smooth steel bands with a slight funnel or cone

shape.

FIGURE 17-34 Two seal guides can be placed into the clutch drum. With the new seals lubricated, the piston can be installed without seal lip damage.



TECH TIP

FIGURE 17-35 An extension housing O-ring seal has been placed over the piston lip seal of this front clutch. It reshapes the sealing lip to make installation easier.



TECH TIP

FIGURE 17-36 After the clutch is completely assembled, the condition of the seals can be verified by an air check. The dial indicator will give an accurate measurement of the clutch pack clearance. (Courtesy of Toyota Motor Sales USA, Inc.)




• Fitting Sealing Rings– A sealing ring has to make a seal on one of its sides and at the outer

diameter. – Fluid pressure plus the elasticity of the ring pushes the ring outward,

where it engages the bore.

FIGURE 17-37 A sealing ring is forced outward, away from the fluid pressure. It tends to wear into the sides of the seal grooves.




FIGURE 17-38 A metal sealing ring has been hooked and placed into its bore. It should enter with a slight pressure and make full contact with the bore. There should be a slight gap at the ends of the ring as shown.




FIGURE 17-39 Side clearance of a metal sealing ring is checked by placing the ring into the groove and measuring the clearance using a feeler gauge (a). While making this check, look for damage to the seal groove (b).




• Installing Teflon Sealing Rings– Scarf-cut, Teflon sealing rings

are easy to install. – Merely place them in the

groove with the ends lapped in the correct direction.

FIGURE 17-40 Compressing a seal ring helps it fit tight in its groove (a). During installation, make sure the

ends interlock properly (b). (Courtesy of Chrysler Corporation)




FIGURE 17-41 This Teflon seal installation set allows you to stretch a seal ring, position it in the groove, and resize the seal so it has the proper fit. (Courtesy of ATEC Trans-Tool and Cleaning Systems)



SUMMARY

1. A transmission overhaul includes disassembly, cleaning, replacing worn parts, and reassembling to its original clearances.

2. Transmission parts are cleaned by hand and by automated wash cabinets.

3. Bushings and bearings are carefully checked and replaced as necessary.

4. Clutches are serviced by inspecting and replacing the friction material and seals.

5. Sealing rings must be replaced and the surfaces they seal against must be carefully inspected and serviced as needed.



REVIEW QUESTIONS

1. Shop rags should never be used to clean, dry, or wipe parts because they leave _________ on the parts that could _________ the filter.

2. The commonly used methods for cleaning transmission parts are:

a. _______________________________________________b. ________________________________________________c. ________________________________________________

3. The condition of a plastic, fiber, or metal thrust washer is judged by the appearance of the _________ and the _________ it runs against.

4. The front _________ bushing and the rear _________ housing bushing are usually replaced during an overhaul.

5. During installation, a bushing must be _________ with any oil grooves of passages.



REVIEW QUESTIONS

6. The _________ plates are usually replaced during a transmission overhaul and the _________ plates are often reused.

7. The bands and friction clutch plates should be soaked in ATF for at least _________ minutes before installation in the transmission.

8. A seal ring should be _________ in its bore before installation.

9. After new seals are installed in a clutch and the clutch is completely assembled, it should be _________ checked for proper operation and leakage.

10. A seal ring seals on its __________ and __________ diameter.



CHAPTER QUIZ

1. During a transmission rebuild, it is good practice to replacea) rubber sealing rings.

b) lined clutch plates.

c) paper and composition gaskets.

d) All of these



CHAPTER QUIZ

2. Student A says that the usual method of cleaning transmission parts is to wash them in solvent and dry them with a shop cloth. Student B says that spray washers are a fast and effective way of cleaning parts. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

3. Student A says that worn or damaged bushings are repaired by driving them out and replacing them with new bushings. Student B says that some bushings are removed by cutting threads in them so a puller bolt can be used. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

4. Student A says that position of the bushing holes or grooves is not important during installation. Student B says that all bushings must be stacked after installation. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

5. Student A says that if a tapered roller bearing cup is worn and needs to be replaced, the rest of the bearing parts also will need to be replaced. Student B says that if a tapered bearing is to be reused it must be installed in its original position. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

6. Student A says that it is good practice to replace all friction materials (lined plates, unlined plates, and bands) when rebuilding a transmission. Student B says that lined friction material must be soaked in ATF before it is installed. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

7. Student A says that an unlined steel clutch plate can be reused if it is smooth and shiny and only has a little bit of “potato chip” warpage. Student B says that a lined plate that shows any darkening should not be reused. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

8. Student A says that seals should always be checked for proper fit before installation. Student B says that seals should never be installed dry. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

9. Student A says that excessive end play causes rapid wear of the sealing rings and possibly the sealing ring groove. Student B says that seal does not rotate in the groove; therefore, the groove could not wear. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B



CHAPTER QUIZ

10.Student A says that Teflon sealing rings require special tools for proper installation. Student B says that warming a Teflon seal with hot water will help to size the seal. Who is correct?a) Student A

b) Student B

c) Both A and B

d) Neither A nor B

OBJECTIVES

Documents

Transcript of OBJECTIVES