310T Drive Train Systems 3 — Questions and Answers
Question 1: During a road test a technician notices a clunking noise when transitioning from acceleration to deceleration. The MOST likely cause is:
- Worn transmission countershaft bearings
- Excessive driveshaft end play or worn U-joints (Correct answer)
- Slipping torque converter clutch
- Low differential oil
Correct answer: Excessive driveshaft end play or worn U-joints
A clunk during torque reversal (power-on to power-off) is a classic symptom of excessive U-joint play or worn slip-yoke splines.
Question 2: When adjusting a manual slack adjuster on a drive axle, the technician should ensure the pushrod stroke at full application does NOT exceed:
- 1.0 inch (25 mm)
- 1.75 inches (44 mm) for a standard 30-type chamber (Correct answer)
- 2.5 inches (64 mm)
- 3.0 inches (76 mm)
Correct answer: 1.75 inches (44 mm) for a standard 30-type chamber
Federal regulations specify maximum pushrod stroke limits by chamber type; a type-30 chamber has a 1.75-inch limit before the brakes are considered out of adjustment.
Question 3: A fully automatic transmission in a transit coach does NOT upshift at the correct vehicle speed. After verifying the throttle position signal is correct, the technician should NEXT check:
- Engine compression
- Turbine speed sensor and output shaft speed sensor signals (Correct answer)
- Clutch pedal adjustment
- Driveshaft phase angle
Correct answer: Turbine speed sensor and output shaft speed sensor signals
The transmission control module uses turbine and output speed sensor signals to calculate the correct shift points.
Question 4: What is the function of the torque converter stator?
- Mechanically lock the impeller to the turbine
- Redirect fluid from the turbine back to the impeller to multiply torque (Correct answer)
- Reduce heat buildup in the converter housing
- Control line pressure in the hydraulic circuit
Correct answer: Redirect fluid from the turbine back to the impeller to multiply torque
The stator redirects returning fluid from the turbine to assist the impeller, which multiplies torque during low-speed acceleration.
Question 5: A technician is replacing a pinion seal on a drive axle. Before installing the new seal, it is MOST important to:
- Replace the ring and pinion gear set
- Check and record pinion bearing preload before disassembly (Correct answer)
- Flush the axle housing with solvent
- Inspect the differential carrier for cracks
Correct answer: Check and record pinion bearing preload before disassembly
Pinion bearing preload must be recorded before disassembly so it can be restored to the original specification during reassembly.
Question 6: Which of the following BEST describes the purpose of a splitter group in a multi-speed transmission?
- It doubles the number of available ratios by splitting each main box gear into two ratios (Correct answer)
- It allows the driver to split the clutch engagement force
- It provides a separate low-range for off-road driving only
- It controls the locking of the inter-axle differential
Correct answer: It doubles the number of available ratios by splitting each main box gear into two ratios
A splitter section adds a direct and an overdrive ratio to each main box position, effectively doubling the total number of gears.
Question 7: In a hydraulically operated clutch system, a spongy clutch pedal feel is MOST likely caused by:
- Low clutch disc friction material
- Air in the hydraulic line (Correct answer)
- Worn pressure plate fingers
- Incorrect flywheel surface finish
Correct answer: Air in the hydraulic line
Air is compressible and creates a spongy feel; the system must be bled to restore firm pedal response.
310T Drive Train Systems 3
During a road test a technician notices a clunking noise when transitioning from acceleration to deceleration.
The MOST likely cause is: