ASE A3 Manual Drive Train and Axles
6. The manual transmission's shifter in a light-duty truck feels loose and has excessive play. Which of the following is MOST likely causing this condition?
- A. A worn shifter bushing.
- B. A worn detent ball and spring.
- C. A bent shift rail.
- D. Bent shift rod linkage.
Answer A is correct. The shift lever bushing is MOST likely at fault. Shifter bushings are plastic bushings and grommets that provide a tight fit and a smooth feel while keeping the shifter firmly in the proper shift rail. View the illustration in the Read more... section.
Answer B is wrong. Shift rails have detent notches machined into their sides. A spring-loaded ball fits into the notch to keep the transmission firmly in gear.
Answer C is wrong. The shift rail should slide easily in its bore and should not have any lateral up and down or side to side movement.
Answer D is wrong. Shift rods are external, and shift rails are inside the transmission. Shift rods require a different type of bushing that provides a tight fit and smooth movement whenever linkage connects.
7. A front-wheel-drive passenger vehicle makes a growling sound that gets louder when turning left. Which of the following is causing this noise?
- A. A faulty right front wheel bearing.
- B. A faulty right front outer CV Joint.
- C. A faulty left front wheel bearing.
- D. Cupped tire treads.
Answer A is correct. A left-hand turn would reveal a faulty right side bearing because the weight and inertia of the vehicle are pushing on the right front wheel.
Answer B is wrong. A faulty outer CV-Joint typically makes a clicking or clacking sound while slowly turning corners.
Answer C is wrong. A right-hand turn would work the left side wheel bearing because the weight of the vehicle has now shifted to the left wheel.
Answer D is wrong. Both cupped tires and faulty wheel bearings cause a similar growling noise while driving. This problem can make it difficult to distinguish between the two in operation. A cupped tire changes its pitch from one surface to another. This change in pitch is true with all tires, but much more pronounced with a cupped or scalloped tire.
8. A vehicle with a limited-slip differential chatters only while taking turns.
- A. A worn clutch causes this chatter.
- B. Using the wrong differential fluid causes chatter.
- C. Both A and B are correct.
- D. Neither A or B is correct.
Answer A is wrong. In time, the friction material wears, and the splines and tabs become rounded. Because limited-slip differentials are designed to provide smooth cornering, the symptoms of a worn or damaged differential can become most apparent while taking turns.
Answer B is wrong. Always use the recommended fluid; special limited-slip differential fluid compliments the engagement and release of the limited-slip components.
Answer C is correct. Both A and B are correct. Limited slip differential's lock the two rear wheels together while traveling in a straight line, but allow one wheel to slip while turning. By overcoming the tension of its clutch, the two wheels are allowed to rotate at different speeds during turns.
Answer D is wrong. Use only the manufacturer’s recommended fluid when servicing a limited-slip differential. Servicing with the wrong type of fluid results in vibration and chatter.
9. The part illustrated above contains:
- A. A sealed wheel bearing.
- B. A hub.
- C. An ABS tone ring.
- D. All of the above.
Answer A is wrong. All of the above answers are correct. It's a picture of a hub and bearing with an ABS tone ring attached.
Answer B is wrong. The hub in the illustration has a sealed bearing installed. One part of the hub attaches to the spindle, and the other part attaches to the wheel; the wheel bearing spins between the two.
Answer C is wrong. ABS systems use wheel speed sensor's to measure wheel speed with the passing teeth of the attached tone or reluctor ring.
Answer D is correct. They support the vehicle's weight as it accelerates, decelerates, and corners. Many have a wheel speed sensor or its companion tone ring incorporated into their design.
10. A front-wheel-drive vehicle is being diagnosed for a faulty axle. Technician A says a faulty outboard CV joint makes its most noise while taking turns. Technician B says a faulty inboard CV joint makes its most noise while accelerating and decelerating. Who is correct?
- A. Technician A
- B. Technician B
- C. Both A and B
- D. Neither A or B
Answer A is wrong. They're both correct; a faulty inboard trunion makes a thunking noise while accelerating and decelerating in a straight line.
Answer B is wrong. A worn or faulty outboard CV-joint makes its most noise while cornering. While road testing, listen for a clicking or clacking noise while slowly taking a sharp left or right-hand turn.
Answer C is correct. Both technicians are correct.
Answer D is wrong. Many of these axles have a vibration damper. If the vehicle suffers from front end vibration that's most apparent at higher speeds, inspect the damper.