ASE A3 Manual Drive Train and Axles

Ring and Pinion gear tooth contact pattern.

16. Tooth contact compound is applied to the ring gear. It's then rotated four revolutions on the drive side, and four revolutions on the coast side. The tooth contact pattern shown above indicates:

  • A. The pinion depth should be increased.
  • B. The pinion depth should be decreased.
  • C. There is insufficient ring gear backlash.
  • D. An ideal ring gear tooth contact pattern.

16.

Ring and Pinion gear tooth contact pattern.

Answer A is correct. The pattern indicates that the pinion depth should be increased. This increase would move the contact pattern closer to the bottom or root of the ring gear.

Answer B is wrong. When the tooth contact pattern is too close to the root of the ring gear, pinion depth should be decreased, moving the pinion away from the ring gear. This decrease would move the tooth contact pattern closer to the top. The contact pattern should be centered between the top and the root or flank of the gear's teeth, not at the top like the illustration.

Answer C is wrong. Adjusting ring gear backlash moves the pattern from the outer end of the ring gear (heel) to the inner end of the ring gear (toe) and visa versa.

Answer D is wrong. An ideal ring gear tooth contact pattern is centered between the top and the bottom of the gear's teeth.

17. A five-speed manual transaxle is hard to shift, and gold-colored shavings are seen in the transmission fluid towards the end of the draining cycle. Which of the following is causing this condition?

  • A. Chipped gear teeth.
  • B. Worn synchronizer blocking rings.
  • C. Casting Slag.
  • D. Loose shift rails.

17.

Answer A is wrong. Metal shavings from a gear's teeth appear like shinny metal or silver, not gold.

Answer B is correct. They're brass shavings. If there is excessive brass in the fluid towards the end of the draining cycle and the vehicle is suffering from hard shifting, the blocking rings are likely worn.

Answer C is wrong. Aluminum pieces indicate transmission case damage or case slag.

Answer D is wrong. A shift rail should slide easily in its bore, but should not have any lateral up and down or side to side movement. Loose shift rails cause hard shifting but would not result in gold-colored flakes in the fluid.

18. The viscous clutch in an AWD vehicle has repeated failure. Which of the following is MOST likely causing this condition?

  • A. An axle seal leak.
  • B. Overfilled fluid.
  • C. Worn universal joints.
  • D. Different size tires.

18.

Answer A is wrong. A leaking axle seal results in fluid draining into the brake unit. Many of today's vehicles have automatic AWD systems that offer additional stability over 2WD systems. These systems provide 2WD during most situations, and only when the primary axle begins to spin does the vehicle enable the other axle, providing AWD.

Answer B is wrong. Overfilled fluid would not likely cause repeated failure.

Answer C is wrong. Universal joints allow the driveshaft to transfer torque at different angles as the vehicle travels over bumps in the road. If worn, they cause a clunk when the transmission is placed into drive or reverse. They also cause driveline vibrations that increase with vehicle speed.

Answer D is correct. The viscous clutch allows for differences in axle rotation. When forced to compensate for different sized tires or inflation, the clutch is overworked and wears prematurely.

19. The clutch on a manual transmission chatters when it's first engaged. All of the following would cause this clutch chatter EXCEPT:

  • A. Contaminated disk friction material.
  • B. A worn pressure plate.
  • C. Chipped gear teeth.
  • D. A worn flywheel.

19.

Answer A is wrong. Clutch chatter is the initial shudder that occurs when a faulty clutch disk or clutch component first engages. Worn or contaminated clutch facings cause clutch chatter and grabbing. Contaminated clutch disk friction material is typically the result of oil leaking from the rear main seal or front transmission pump seal.

Answer B is wrong. Pressure plates wear, and the springs become weak resulting in chatter and slipping.

Answer C is correct. Inspect the gear’s teeth for chipping and excessive wear. Worn and rounded gear teeth cause a growling noise. This grinding or growling noise may be evident in all gears but is more pronounced when it’s the selected gear.

Answer D is wrong. A worn or warped pressure plate results in clutch chatter. The clutch disc is grabbing and releasing the flywheel and pressure plate as the assembly is turning.

20. A manual transmission has a growling sound that gets louder in second gear. Technician A says the second gear has a chipped tooth. Technician B says the synchronizer's blocking rings are rounded. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

20.

Answer A is correct. Chipped and rounded gear teeth cause a growling or grinding noise. This noise may be evident in all gears but is more pronounced when it's the selected gear.

Answer B is wrong. Today's transmission contains synchronizers that slide on the main shaft and over the selected gear's dog teeth to match the shaft and gears speed before complete engagement.

Answer C is wrong. This noise may be evident in all gears but is more pronounced when it's shifted into second gear.

Answer D is wrong. Today's transmission remains in constant mesh. Synchronizers dramatically reduce the chance of breaking and chipping the gear's teeth.