CTE Transmission & Drivetrain Systems 3 — Questions and Answers
Question 1: What happens to engine braking effectiveness when a driver downshifts in a manual transmission?
- Engine braking decreases because the clutch disengages
- Engine braking increases because the engine acts as a load on the drivetrain (Correct answer)
- Engine braking is unaffected by gear selection
- Engine braking only occurs in reverse gear
Correct answer: Engine braking increases because the engine acts as a load on the drivetrain
Downshifting increases engine braking by forcing the engine to spin faster, creating more resistance (compression braking) that slows the vehicle.
Question 2: A CVT (Continuously Variable Transmission) achieves variable gear ratios using which mechanism?
- Planetary gear sets with multiple clutch packs
- Variable-diameter pulleys connected by a drive belt or chain (Correct answer)
- Electronically controlled synchronizer rings
- Hydraulic torque multiplication through multiple fluid circuits
Correct answer: Variable-diameter pulleys connected by a drive belt or chain
CVTs use two variable-diameter pulleys connected by a belt or chain; changing the effective diameter of each pulley continuously varies the gear ratio.
Question 3: What is the purpose of the ring and pinion gear set in a rear axle differential?
- To synchronize wheel speeds during cornering
- To change the direction of power flow 90 degrees and provide a final drive ratio (Correct answer)
- To lock the differential during high-traction conditions
- To convert fluid pressure into mechanical rotation
Correct answer: To change the direction of power flow 90 degrees and provide a final drive ratio
The ring and pinion gears redirect torque 90 degrees from the driveshaft to the axle shafts and establish the final drive ratio.
Question 4: Which symptom most likely indicates a worn CV axle boot on a front-wheel-drive vehicle?
- Vibration felt only at highway speeds
- Clicking or popping noise during low-speed turns (Correct answer)
- Transmission slipping between gears
- Steering wheel pulling to one side under braking
Correct answer: Clicking or popping noise during low-speed turns
A torn CV boot allows grease to escape and contamination to enter the joint, causing clicking or popping noises particularly during slow, tight turns.
Question 5: In a four-wheel-drive system, what is the role of the transfer case?
- Replace the rear differential when driving off-road
- Split and distribute torque between the front and rear axles (Correct answer)
- Convert the automatic transmission into a manual mode
- Regulate hydraulic pressure to all four wheel brakes
Correct answer: Split and distribute torque between the front and rear axles
The transfer case receives power from the transmission and splits it between the front and rear driveshafts, enabling four-wheel-drive operation.
Question 6: Which planetary gear set component is held stationary to achieve a speed reduction (underdrive)?
- Sun gear
- Ring gear (Correct answer)
- Carrier (planet carrier)
- Output shaft
Correct answer: Ring gear
Holding the ring gear stationary while applying input to the sun gear and taking output from the carrier produces a speed reduction.
Question 7: A CTE automotive instructor wants to assess students' understanding of drivetrain power flow. Which assessment best measures applied knowledge?
- Multiple-choice test on component names only
- Students trace and explain power flow through a disassembled drivetrain on a workbench (Correct answer)
- Oral quiz reciting gear ratio formulas
- Essay describing the history of automotive transmissions
Correct answer: Students trace and explain power flow through a disassembled drivetrain on a workbench
Having students physically trace power flow through actual components demonstrates applied understanding and aligns with CTE's competency-based assessment model.
CTE Transmission & Drivetrain Systems 3
What happens to engine braking effectiveness when a driver downshifts in a manual transmission?