310S Drivetrain and Transmission 1 — Questions and Answers
Question 1: What is the primary function of the torque converter in an automatic transmission?
- To shift gears automatically
- To transfer and multiply engine torque to the transmission using hydraulic fluid coupling (Correct answer)
- To lock the transmission in park
- To cool the transmission fluid
Correct answer: To transfer and multiply engine torque to the transmission using hydraulic fluid coupling
The torque converter uses hydraulic fluid to transfer engine torque to the transmission input shaft. At low speeds, it multiplies torque through the stator element, providing a mechanical advantage similar to a low gear.
Question 2: What causes a vibration felt throughout the vehicle during acceleration from a stop?
- Unbalanced tires
- Worn universal joints (U-joints) on the driveshaft (Correct answer)
- A faulty ignition coil
- Low power steering fluid
Correct answer: Worn universal joints (U-joints) on the driveshaft
Worn U-joints develop play that causes the driveshaft to vibrate during acceleration. The vibration is typically felt at low speeds and during acceleration when the most torque is transmitted through the drivetrain.
Question 3: What is the purpose of the clutch release (throw-out) bearing in a manual transmission?
- To engage the clutch when the pedal is released
- To contact and push against the rotating pressure plate fingers when the clutch pedal is depressed, disengaging the clutch (Correct answer)
- To support the transmission input shaft
- To lubricate the clutch disc splines
Correct answer: To contact and push against the rotating pressure plate fingers when the clutch pedal is depressed, disengaging the clutch
The throw-out bearing slides forward when the clutch pedal is pressed, contacting the rotating pressure plate diaphragm spring fingers. Being a bearing, it allows the stationary fork to push against the spinning pressure plate.
Question 4: What does burnt-smelling automatic transmission fluid (ATF) indicate?
- Normal fluid aging
- The transmission has overheated, degrading the fluid and potentially damaging friction components (Correct answer)
- Contamination from engine oil
- The fluid needs topping up
Correct answer: The transmission has overheated, degrading the fluid and potentially damaging friction components
Burnt ATF has a dark brown or black colour with a burnt smell, indicating excessive heat has broken down the fluid's lubricating and friction-modifying properties. Overheating damages clutch packs, seals, and other components.
Question 5: What is the function of the differential in the drivetrain?
- To multiply engine torque at all times
- To allow the drive wheels to rotate at different speeds during turns while distributing power to both wheels (Correct answer)
- To connect the engine to the transmission
- To lock the rear wheels for traction
Correct answer: To allow the drive wheels to rotate at different speeds during turns while distributing power to both wheels
During a turn, the outer wheel must travel farther and rotate faster than the inner wheel. The differential's spider gears allow this speed difference while continuing to deliver torque to both wheels.
Question 6: What causes a clicking noise from the front axle area when turning at low speed in a front-wheel-drive vehicle?
- Worn wheel bearings
- A worn outer CV (constant velocity) joint (Correct answer)
- Low power steering fluid
- Loose brake caliper bolts
Correct answer: A worn outer CV (constant velocity) joint
The outer CV joint operates at maximum angle during tight turns. When worn, the balls in the joint develop play in their grooves, producing a rhythmic clicking that corresponds to wheel rotation speed.
310S Drivetrain and Transmission 1
What is the primary function of the torque converter in an automatic transmission?