OBJECTIVES

2. OBJECTIVES After studying Chapter 19, the reader should be able to: • Diagnose torque converter and torque converter clutch problems. • Explain the conditions when a torque converter should be reused or rebuilt. • Describe the procedure used to rebuild a torque converter. • Complete the ASE tasks related to torque converter inspection.

3. INTRODUCTION • A torque converter is considered to be part of the transmission. • It should be serviced or replaced when a transmission is overhauled. • A torque converter is always replaced with a new or rebuilt unit if it has an internal failure. • Most shops do not rebuild torque converters. • There are companies that specialize in torque converter overhaul. • A torque converter does not usually wear out and require replacement. • Many shops flush and check the torque converter during every transmission overhaul.

4. FIGURE 19-1 This cutaway view shows where debris and foreign material will tend to collect inside of the outer rim of a torque converter. (Courtesy of Chrysler Corporation) INTRODUCTION

5. TORQUE CONVERTER CHECKS • The torque converter should be checked to make sure it is in usable condition when the transmission is removed. • These checks include the visual condition, stator one-way clutch operation, turbine end play, internal interference, lock-up clutch operation, and external leakage.

6. FIGURE 19-2 Converter inspection begins with visual checks to ensure that the pilot, drive lugs, ring gear (if used), hub, and pump drive tangs are in good condition. TORQUE CONVERTER CHECKS • Visual Checks • The first checks performed are visual. • A technician often performs a visual inspection as the torque converter is removed from the transmission.

7. FIGURE 19-3 A bad starter ring gear can be changed by cutting the welds using a hack saw or grinder and driving the old gear off. The new gear must be secured by welding following the procedure recommended by the manufacturer.(Courtesy of Chrysler Corporation) TORQUE CONVERTER CHECKS

8. FIGURE 19-4 A stator clutch can be checked by reaching into the hub so your finger contacts the splines. You should be able to rotate the splines in one direction but not the other. TORQUE CONVERTER CHECKS • Stator One-Way Clutch Check • There are several ways to check a stator one-way clutch. • The stator clutch must lock in one direction and slip or freewheel in the other. • To check a one-way clutch, you should:

9. FIGURE 19-5 A stator clutch can be checked by gripping the splines using snap-ring pliers. Rotate the splines quickly; in only one direction, you should feel the weight of the stator. TECH TIP • Grip the stator splines using long, thin, flat-jaw snap-ring pliers in order to rotate the stator.

10. FIGURE 19-6 The major wear points inside a torque converter are these thrust surfaces. Internal end play increases as these surfaces wear. TORQUE CONVERTER CHECKS • End-Play Check • Thrust washers at the stator and turbine control internal end play.

11. FIGURE 19-7 The special tool is locked into the turbine. Moving the tool handle up and down allows the end play to be read on the dial indicator. TORQUE CONVERTER CHECKS

12. FIGURE 19-8 The torque converter is placed onto the end-play fixture. After setting the dial indicator to zero (0), the handle is moved downward to lift the turbine and read the end play. (Courtesy of TCRS Inc.) TORQUE CONVERTER CHECKS

13. FIGURE 19-9 A quick end-play check can be made by gripping the turbine or stator splines and trying to move the turbine or stator in and out. TECH TIP • Turbine or stator clutch end play can be checked by gripping the splines with a pair of snap-ring pliers or your fingers.

14. TORQUE CONVERTER CHECKS • Internal Interference Checks • The thrust washers inside a torque converter can wear to the point where the impeller, turbine, or stator can rub against each other. • The normal wear pattern caused by the dynamic fluid pressure moves the turbine toward the front of the torque converter and the stator toward the rear. • Torque converter interference should be checked twice: Once with the turbine and stator toward the front and again with them toward the rear. • To check a converter for internal interference, you should:

15. FIGURE 19-10 An internal interference check. The pump body with stator support (a) and clutch with turbine shaft (b) have been installed and are rotated to feel and listen for internal contact. The assembly is then turned upside down and the checks are repeated. Internal contact in either position indicates a faulty converter. TORQUE CONVERTER CHECKS

16. TORQUE CONVERTER CHECKS • Torque Converter Clutch Checks • Two styles of testers are available for checking torque converter clutches. • One type uses adapters that replace the turbine shaft and allow a vacuum to be exerted on the front side of the clutch plate assembly. • If this chamber can hold a vacuum, the center seal and the clutch lining (which forms the outer seal) are good. • The second tester style uses adapters that attach to the turbine, which uses air pressure to apply the clutch

17. FIGURE 19-11 A torque converter lock-up dyno. It tests the TCC to make sure that it will lock up properly. (Courtesy of TCRS Inc.) TORQUE CONVERTER CHECKS

18. FIGURE 19-12 This torque converter leak-test fixture has adapters to fit hubs of different diameters (a). A different tester is shown with a converter installed (b). (a courtesy of Kent-Moore) TORQUE CONVERTER CHECKS • Leak Checks • A torque converter can leak at the welds, fittings, or plugs. • Leaking fluid will show up at the bottom of the torque converter housing and can be mistaken for a front seal leak. • The difference is the location of wetness on the torque converter.

19. FIGURE 19-13 A leak test fixture has been placed on the torque converter. It will be inflated with air pressure, and then soapy water will be sprayed on it to identify any leaks. TORQUE CONVERTER CHECKS • To check a torque converter for leaks, you should:

20. FIGURE 19-14 Pinhole leaks in a converter can be sealed using a punch and hammer. A series of punch marks around the hole should displace metal to close off the hole. TECH TIP • Very small pinhole leaks can be sealed by peening the hole closed. • This is done using a punch and hammer and striking the area immediately around the hole.

21. TORQUE CONVERTER CLEANING • Torque converters are very difficult to clean because of their internal shape. • Most shops use rebuilt torque converters to ensure a completely clean unit without any concerns of internal wear or damage. • A torque converter cleaner is an effective but expensive piece of equipment. • It pumps cleaning solvent under pressure through the torque converter in a reverse direction, and at the same time, the device rotates the turbine in order to create a fluid flow that loosens the debris so it can be flushed out. • The cleaning operation usually runs until the solvent leaving the torque converter runs clear, about 5 to 15 minutes.

22. TORQUE CONVERTER CLEANING • Drilling a Torque Converter • It is possible to drill a torque converter to provide a drain opening. • This requires installing a plug to seal the opening. • Drilling a torque converter is not generally recommended. • Cooler Cleaning • Cooler cleaners are designed to clean the radiator oil cooler by forcing cleaning solution or fluid through the cooler lines. • This can also be done with a simple fluid pump

23. FIGURE 19-15 A hole can be drilled into the torque converter so that it can be drained. This hole should be tapped to accept a small pipe plug. TECH TIP • When drilling a torque converter, it is important not to drill into any of the internal components. • Drill only deep enough to penetrate the cover and preferably, into the impeller area

24. FIGURE 19-17 A cooler flusher is connected to the cooler lines so a cleaning agent can be forced in the reverse direction through the cooler unit until it is clean. FIGURE 19-16 This cooler line flusher pumps heated flushing solution through the cooler lines and cooler. A flow meter is used to ensure that the cooler is flowing properly and not plugged. (Courtesy of G-Tec) TORQUE CONVERTER CLEANING

25. FIGURE 19-18 A cooler can be back-flushed using an aerosol flushing kit. (Courtesy of Life Automotive Products Inc.) TECH TIP • Flush kits consisting of an aerosol can of flushing solution with adapters to connect to the cooler are available.

26. TORQUE CONVERTER REBUILDING • A torque converter is rebuilt by cutting it open, cleaning and inspecting the parts, replacing any worn or damaged parts, and welding it back together. • Expensive specialized equipment is required to rebuild a torque converter. • The equipment operator should have some machining and metalworking skills. • These requirements limit torque converter rebuilding to companies that specialize in torque converter rebuilding or the larger transmission shops.

27. TORQUE CONVERTER REBUILDING • Rebuilding a torque converter consists of the following operations: • Inspect the exterior for damage. • Cut the torque converter open on a specially equipped lathe. • Inspect the interior components for wear or damage. • Thoroughly clean the interior parts. • Disassemble and inspect the stator one-way clutch. • Replace all worn or damaged parts. • Prelubricate the internal bearing surfaces. • Adjust the internal end play. • Carefully reassemble and weld the two sections together. • Leak check all welds. • Balance the assembly.

28. FIGURE 19-19 This worn converter hub has been removed to allow replacement (a). A new hub has been installed and welded in place using a special welder (b). TORQUE CONVERTER REBUILDING • Disassembling a Torque Converter • Since a torque converter is welded together, the weld must be cut to open the torque converter. • The torque converter is mounted in a metal-cutting lathe for the cutting operation.

29. FIGURE 19-20 To rebuild a converter, first cut it open on a machine lathe (a). A carbide tool is used to cut the weld so the converter can be split apart (b). TORQUE CONVERTER REBUILDING

30. FIGURE 19-21 After being cut open, the usable components are placed in a spray washer for thorough cleaning. TORQUE CONVERTER REBUILDING • Cleaning • A hot spray washer is used to clean the disassembled torque converter parts.

31. TORQUE CONVERTER REBUILDING • Subassembly Repair • With the torque converter disassembled, the following items are checked and repaired as necessary: • Torque converter hub: removed and replaced • Starter ring gear: removed and replaced • Crankshaft pilot: welded to build up material and machined back to original size • Drive lugs/studs: removed and replaced • Turbine drive hub: removed and replaced • Thrust washers: removed, lubricated, and replaced or upgraded to Torrington bearings • Support bushings: removed and replaced • Impeller fins: spot welded to lock in place • Stator clutch: disassembled, inspected, lubricated, and reassembled • Stator clutch outer race: pinned to lock into the stator • Clutch lining: relined • Damper springs or assemblies: removed and replaced

32. FIGURE 19-22 A new starter ring gear has been installed and tack welded. After ensuring that it is straight, it will be welded securely. TORQUE CONVERTER REBUILDING

33. FIGURE 19-23 This torque converter piston bonder is used to bond new lining onto a torque converter clutch piston. (Courtesy of TCRS Inc.) TORQUE CONVERTER REBUILDING

34. TORQUE CONVERTER REBUILDING • Torque Converter Reassembly • Torque converter reassembly requires several operations: • Check the height of the stacked components to ensure that the assembled unit is not too long or too short. • Check and adjust the internal clearance to ensure there is correct end play. Adjustment is done by changing or shimming the thrust washers. • Make sure the bowl and impeller housings are correctly aligned so there is a minimum of hub runout, and tack weld them securely into position. • Weld the housing in an automatic wire welder to provide a continuous, leak-free weld.

35. FIGURE 19-24 This fixture is used to ensure that the converter will have the correct overall length after assembly. Shims are added internally to correct end play if necessary. TORQUE CONVERTER REBUILDING

36. FIGURE 19-25 This converter is assembled, and the two housings are tack welded together (a). Checks made at this time ensure that the hub is centered and true with the front of the converter (b). TORQUE CONVERTER REBUILDING

37. FIGURE 19-26 The assembled converter is welded together on an automatic welder. TORQUE CONVERTER REBUILDING

38. FIGURE 19-27 This converter is pressure tested for leaks in this special fixture. Soap will be sprayed on it, and bubbles will show any leaks. TORQUE CONVERTER REBUILDING • Post-assembly Checks • After the torque converter has been welded back together, it is pressure checked for no leaks

39. FIGURE 19-28 This converter is balanced using a special balancer. Small weights will be spot welded onto it to correct any unbalance. TORQUE CONVERTER REBUILDING

40. SUMMARY • When a transmission is rebuilt, the torque converter is serviced, rebuilt, or replaced. • If a torque converter is to be reused, it should be visually inspected for leaks, the one-way clutch operation checked, and internal end play should be measured. • Torque converters are rebuilt by disassembling them. They are then inspected, cleaned, parts replaced as necessary, adjusted, and reassembled.

41. REVIEW QUESTIONS • Torque converters should be checked for: • _________ • _________ • _________ • _________ • _________ • _________ • The six areas of a torque converter that are visually checked are: • Housing for _________ • Drive lugs or _________ for damage • Pilot for damage or _________ • Hub for signs of seal or _________ wear • _________ drive tangs or lugs for wear or damage • Starter _________ gear for wear or damage

42. REVIEW QUESTIONS • If the stator one-way clutch can be easily turned in both directions, it is said to be _________. • A customer concern about poor fuel economy or higher-than normal engine speed could be the result of a _________ stator clutch. • As a rule of thumb, the torque converter should have no more than _________ end play. • A check for a leaking torque converter is to _________ it and spray it with soapy water. • Transmission coolers are flushed out by forcing _________ through the cooler in a reverse direction. • Torque converters are welded together and must be _________ to be rebuilt.

43. CHAPTER QUIZ • Student A says that a dirty torque converter can ruin a transmission rebuild. Student B says that most used torque converters are worn out. Who is correct? • Student A • Student B • Both A and B • Neither A nor B

44. CHAPTER QUIZ • Student A says that a dirty torque converter can ruin a transmission rebuild. Student B says that most used torque converters are worn out. Who is correct? • Student A • Student B • Both A and B • Neither A nor B

45. CHAPTER QUIZ 2. The visual checks to be made on a torque converter include the condition of the • drive lugs or studs. • hub and pump drive tangs. • pilot. • All of these

46. CHAPTER QUIZ 2. The visual checks to be made on a torque converter include the condition of the • drive lugs or studs. • hub and pump drive tangs. • pilot. • All of these

47. CHAPTER QUIZ 3. Student A says that it should not be possible to turn the stator splines in either direction with one’s finger. Student B says that normally these splines can be turned both ways by gripping them with a pair of snap-ring pliers. Who is correct? • Student A • Student B • Both A and B • Neither A nor B

48. CHAPTER QUIZ 3. Student A says that it should not be possible to turn the stator splines in either direction with one’s finger. Student B says that normally these splines can be turned both ways by gripping them with a pair of snap-ring pliers. Who is correct? • Student A • Student B • Both A and B • Neither A nor B

49. CHAPTER QUIZ 4. Student A says that a torque converter with a bad stator oneway clutch should be replaced with a new torque converter. Student B says a torque converter can be rebuilt and the oneway clutch repaired. Who is correct? • Student A • Student B • Both A and B • Neither A nor B

50. CHAPTER QUIZ 4. Student A says that a torque converter with a bad stator oneway clutch should be replaced with a new torque converter. Student B says a torque converter can be rebuilt and the oneway clutch repaired. Who is correct? • Student A • Student B • Both A and B • Neither A nor B