ASE A3 Manual Drive Train and Axles
1. A vehicle with a five-speed manual transmission has a squealing sound when the clutch pedal is first depressed. Which of the following is causing this noise?
- A. The pilot bearing.
- B. The clutch release bearing.
- C. The flywheel.
- D. A worn synchronizer.
Answer A is wrong. When the clutch is disengaged, the transmission's input shaft and the engine's crankshaft are rotating at different speeds. The pilot bearing allows for this difference. A bad pilot bearing makes its most noise when the clutch pedal is completely depressed, and the clutch itself is completely disengaged.
Answer B is correct. A faulty clutch release bearing can be heard squealing when the clutch pedal is depressed. It starts squealing or chirping when the bearing contacts the pressure plate's diaphragm fingers.
Answer C is wrong. The surface area of the flywheel must be smooth and not warped. Warpage reduces the contact area of the flywheel, allowing it to slip. This slipping causes excessive heat, hotspots, and glazing.
Answer D is wrong. A worn synchronizer affects only a specific gear range.
2. A longitudinal transmission has repeated extension housing seal failure. Which of the following is LEAST likely to cause this repeated failure?
- A. U-joint failure.
- B. A pitted slip yolk.
- C. Excessive input shaft endplay.
- D. A clogged vent.
Answer A is wrong. A faulty universal joint causes vibration and movement, resulting in the premature bushing and seal failure.
Answer B is wrong. A pitted slip yolk can cause repeated extension housing seal failure.
Answer C is correct. Excessive input shaft endplay is not likely to damage the extension housing seal.
Answer D is wrong. A clogged vent will cause pressure to build as the transmission heats up. This pressure will cause fluid to bypass or damage the extension housing seal.
3. The indicator light continues to flash after shifting a vehicle from 2WH to 4WH. The vehicle does not complete the shift and remains in 2WH. Technician A says a defective shift motor could cause this problem. Technician B says a bent actuator shift fork will result in this condition. Who is correct?
- A. Technician A
- B. Technician B
- C. Both A and B
- D. Neither A or B
Answer A is wrong. This problem is typically caused by faulty wiring or an electrical component like the controller, a faulty shift motor or fork, a speed sensor, or the position switch.
Answer B is wrong. If the actuator (motor) or its shift fork is faulty, the vehicle will remain in 2WD, and the light will flash, indicating a problem to the driver.
Answer C is correct. Both technicians are correct.
Answer D is wrong. Most of today's transfer cases are electronic and require a controller.
4. A technician is testing a clutch safety switch in a vehicle with a no-start condition. All of the following are correct about this switch EXCEPT:
- A. The clutch safety switch is a member of the starting system.
- B. Use a multimeter to test a clutch safety switch.
- C. Use a multimeter to diagnose the clutch safety switch circuit.
- D. The meter should display continuity 0.00 with the pedal out and the switch contacts open.
Answer A is wrong. The clutch start safety switch is a member of the starting system.
Answer B is wrong. Use a multimeter to diagnose the clutch switch and circuit.
Answer C is wrong. The clutch safety switch is normally open when the clutch pedal is released and closes to complete the circuit when the pedal is depressed.
Answer D is correct. On a good switch, the meter should display infinity OL with the switch open and the pedal out, not depressed. If the switch is stuck closed the vehicle would start even with the clutch pedal out and the clutch engaged. This is hazardous.
5. A vehicle with a vacuum brake booster and a five-speed manual transmission has a small drip of tan-colored fluid on the driver's side floorboard. Which of the following is MOST likely causing this leak?
- A. Leaking brake master cylinder cup seals.
- B. A leaking clutch master cylinder secondary seal.
- C. A leaking brake vacuum booster check valve.
- D. A leaking clutch master cylinder primary seal.
Answer A is wrong. A clutch master cylinder uses a single-piston that works similar to a brake master cylinder. Leaking brake master cylinder cup seals cause the brake pedal to fade to the floorboard.
Answer B is correct. The primary seal leaks internally, and the secondary seal leaks externally. A leaking secondary seal will result in fluid dripping from the clutch master on to the driver's side floor panel.
Answer C is wrong. A leaking brake vacuum booster check valve causes a low source vacuum and a hard brake pedal.
Answer D is wrong. A leaking clutch master cylinder's internal or primary seal results in a loss in pressure and clutch slippage.