ASE Automobile (A1–A8) — All Questions

In an automatic transmission, the torque converter's function is to:

• a.Engage the parking pawl
• b.Couple the engine to the transmission and multiply torque✓
• c.Generate line pressure directly
• d.Cool the engine oil

The torque converter is a fluid coupling that transmits power from the engine to the transmission and multiplies torque during acceleration. Its lockup clutch mechanically links the engine and transmission at cruise to improve fuel economy. The pump, not the converter, generates line pressure.

Technician A says burnt-smelling, dark automatic transmission fluid can indicate overheating and clutch damage. Technician B says fluid color and smell never matter. Who is correct?

• a.Technician B only
• b.Both A and B
• c.Neither A nor B
• d.Technician A only✓

Dark, burnt-smelling ATF indicates overheating and worn friction material from slipping clutches or bands. Healthy fluid is typically red and translucent. Technician B is wrong because fluid condition is an important diagnostic clue.

A manual transmission clutch that slips under load, especially in higher gears, most commonly indicates:

• a.Too much clutch pedal free play
• b.A broken motor mount
• c.A dry pilot bearing
• d.A worn clutch disc or weak pressure plate✓

A worn friction disc or weak pressure plate cannot hold torque, so the clutch slips under load and engine rpm rises without matching acceleration. Slipping generates heat that accelerates wear. Insufficient free play, not too much, can also cause slipping.

Constant-velocity (CV) joints are used on front-wheel-drive axles primarily because they:

• a.Transmit power smoothly through varying steering angles✓
• b.Are cheaper than U-joints
• c.Require no lubrication
• d.Eliminate the need for a differential

CV joints deliver constant rotational speed while the axle operates through the wide angles created by steering and suspension travel. A torn CV boot lets grease escape and dirt enter, leading to a clicking noise during turns. Boot inspection is a routine maintenance check.

A clicking noise from the front of a FWD vehicle that increases when turning sharply is most likely caused by:

• a.A worn outer CV joint✓
• b.An unbalanced tire
• c.A leaking transmission seal
• d.A worn wheel bearing

A worn outer CV joint clicks under the load of a sharp turn, and the noise usually worsens with steering angle. A torn boot that allowed grease loss is a frequent cause. Wheel bearing noise, by contrast, is typically a steady drone that changes with vehicle speed.

The differential in a rear axle allows:

• a.The transmission to shift gears
• b.The drive wheels to rotate at different speeds during turns✓
• c.The driveshaft to change length
• d.The engine to idle smoothly

The differential splits torque to the drive wheels while allowing them to turn at different speeds when cornering, since the outer wheel travels farther. A limited-slip design adds resistance to reduce wheel spin. Whining or howling noises often indicate worn or improperly set-up gears.

Technician A says a worn driveshaft U-joint can cause a clunk on acceleration. Technician B says it can cause a vibration that increases with vehicle speed. Who is correct?

• a.Neither A nor B
• b.Technician A only
• c.Both A and B✓
• d.Technician B only

A worn universal joint clunks when torque is applied and vibrates more as speed rises because the joint develops play. Both technicians describe valid symptoms. Rust-colored dust around the caps is an early sign of failure.

A vehicle has a final drive ratio of 3.73:1. This means the:

• a.Driveshaft turns 3.73 times for each wheel revolution✓
• b.Engine turns at 3.73 percent of wheel speed
• c.Transmission has 3.73 forward gears
• d.Wheels turn 3.73 times per driveshaft revolution

A 3.73:1 final drive means the driveshaft (ring-and-pinion input) turns 3.73 times for every one revolution of the axle/wheel. A numerically higher ratio improves acceleration but raises cruising rpm. Ratio is found by dividing ring-gear teeth by pinion-gear teeth.

Technician A says most dipstick-equipped automatics are checked with the engine running at operating temperature. Technician B says fluid level is unaffected by temperature. Who is correct?

• a.Technician B only
• b.Neither A nor B
• c.Technician A only✓
• d.Both A and B

Dipstick-equipped automatics are checked hot with the engine running and the selector cycled, and fluid expands with temperature so the reading depends on it. Technician B is wrong. Many modern units use a sealed fill within a specified fluid-temperature window.

Technician A says a slipping band or clutch pack can cause delayed or harsh shifts. Technician B says low line pressure can cause slipping and overheating. Who is correct?

• a.Both A and B✓
• b.Technician A only
• c.Technician B only
• d.Neither A nor B

Worn friction elements slip and cause delayed, harsh, or flaring shifts, while low line pressure reduces clamping force and leads to slippage and heat. Both conditions are valid causes of shift complaints. A pressure test and scan-tool data help isolate the fault.

Excessive clutch pedal free play in a manual transmission can cause:

• a.Loss of transmission fluid
• b.The flywheel to warp
• c.Incomplete clutch release, making shifting difficult✓
• d.The clutch to slip under load

Too much free play prevents the clutch from fully disengaging, causing grinding or hard shifting because the disc still contacts the flywheel. Too little free play causes slipping. Hydraulic systems self-adjust, while cable systems may require manual adjustment.

A gear ratio is calculated by dividing the number of teeth on the driven gear by the number on the drive gear. A drive gear with 12 teeth turning a driven gear with 36 teeth produces a ratio of:

• a.2:1
• b.3:1✓
• c.4:1
• d.1:3

Dividing 36 driven teeth by 12 drive teeth gives a 3:1 reduction, meaning the drive gear turns three times for each output revolution. This multiplies torque while reducing speed. Understanding ratios is essential for diagnosing driveline gearing and speedometer calibration.

A whining noise from an automatic transmission that changes with engine speed but is present in Park and Neutral most likely points to:

• a.A slipping clutch pack
• b.A worn output shaft bearing
• c.A worn CV joint
• d.A failing transmission fluid pump✓

Because the pump is driven by the converter hub whenever the engine runs, a pump-related whine is present in Park and Neutral and varies with engine rpm. Output-related noises appear only when the vehicle moves. Low fluid or aeration can produce similar sounds.

The pilot bearing or bushing in a manual-transmission vehicle supports the:

• a.Throwout bearing
• b.Tip of the transmission input shaft✓
• c.Flywheel ring gear
• d.Clutch release fork

The pilot bearing supports the front tip of the input shaft in the end of the crankshaft, keeping it centered. A worn pilot bearing causes noise and hard shifting, especially with the clutch depressed. It should be inspected or replaced whenever the clutch is serviced.

A shudder at light throttle around 40-50 mph that smooths out under harder acceleration most likely indicates:

• a.An unbalanced tire producing a vibration only at highway speed
• b.A worn outer CV joint that clicks and shudders during tight turns
• c.A torque converter clutch (lockup) shudder✓
• d.A slipping serpentine belt losing grip on the accessory pulleys

TCC shudder appears when the converter clutch applies at cruise, often from worn friction material or degraded fluid, and it disappears when the clutch releases under heavier throttle. Fresh fluid of the correct type sometimes cures early shudder. Scan data confirms lockup timing.

In a modern electronically controlled automatic, shift points are determined mainly by the:

• a.Mechanical governor and vacuum modulator working entirely on their own
• b.Throttle cable position acting alone with no electronic input at all
• c.A driver-adjustable vacuum valve mounted on the intake manifold
• d.Control module using sensor inputs and shift solenoids✓

Electronic automatics use the control module reading throttle, speed, and load to command shift solenoids, replacing the old governor and vacuum modulator. This allows adaptive, precise shifting. Faults set codes read with a scan tool.

The valve body in an automatic transmission functions to:

• a.Generate the engine's intake vacuum used by the accessory systems
• b.Direct hydraulic fluid to apply the correct clutches and bands✓
• c.Charge the battery through a gear-driven generator inside the case
• d.Cool the engine oil by passing it through internal fluid passages

The valve body is the hydraulic control center that routes pressurized fluid to the apply devices for each gear, guided by the solenoids and pump pressure. A stuck valve causes shift complaints. It works with the electronic controls to time shifts.

Planetary gearsets are used in automatic transmissions mainly because they can provide:

• a.Several gear ratios plus reverse in a compact, strong unit✓
• b.Electrical power generation to help run the vehicle's accessories
• c.Cooling for the engine by circulating fluid through the gearset
• d.Only one fixed ratio, which keeps the whole assembly very simple

By holding or driving different members, a planetary set delivers several forward ratios plus reverse in a compact package that stays in constant mesh. This makes automatic shifting smooth and durable. Clutches and bands control which members are held.

An automatic transmission will not move in any gear, forward or reverse. A likely cause is:

• a.A single worn synchronizer preventing engagement of just one gear
• b.A dragging brake caliper holding the vehicle back on one wheel
• c.A worn outer CV joint that has begun to click loudly during turns
• d.Very low fluid or a failed pump producing no line pressure✓

No movement in any range points to a loss of hydraulic pressure from low fluid or a failed pump, since pressure applies every gear. A pressure test confirms it. Synchronizers exist only in manual transmissions.

A manual transmission grinds only when shifting into one particular gear. The MOST likely cause is:

• a.A low engine oil level starving the transmission of lubrication
• b.A worn front wheel bearing that drones and roughens with speed
• c.A slipping serpentine belt losing grip under accessory drive load
• d.A worn synchronizer for that specific gear✓

A synchronizer matches shaft speeds so the gear engages smoothly; when one wears, that specific gear grinds while others shift fine. Clutch drag can also cause grinding but usually affects all gears. Replacing the worn synchro corrects it.

The synchronizer in a manual transmission functions to:

• a.Generate line pressure that applies the clutches during each shift
• b.Match gear and shaft speeds for smooth, clash-free engagement✓
• c.Engage the starter motor with the flywheel ring gear when cranking
• d.Lubricate the clutch disc so it engages the flywheel more smoothly

The synchronizer brings the rotating gear and shaft to the same speed before the collar locks them, preventing clash. Worn synchros cause grinding in that gear. Double-clutching can help engage a transmission with weak synchros.

A manual-transmission clutch that chatters (shudders) as it engages is most often caused by:

• a.An oil-soaked disc or a worn or warped component✓
• b.A stuck-closed engine thermostat causing the engine to run cold
• c.An overcharged air conditioning system raising the high-side pressure
• d.Too much brake fluid in the hydraulic clutch master cylinder

Chatter usually comes from a glazed or oil-soaked disc, a warped flywheel, or worn parts that grab unevenly during engagement. A leaking rear main or input seal can soak the disc. Correcting the leak and replacing the disc cures it.

A hydraulic clutch pedal that goes to the floor and will not disengage the clutch most likely has:

• a.A worn front wheel bearing that has developed play and roughness
• b.Low fluid or air in the clutch hydraulics, or a failed cylinder✓
• c.A warped brake rotor causing a pulsation through the brake pedal
• d.A clogged cabin air filter restricting airflow from the HVAC vents

Loss of hydraulic pressure from low fluid, air, or a leaking master or slave cylinder prevents the clutch from releasing, so the pedal feels dead. Bleeding and repairing the leak restores operation. The clutch hydraulic system is separate from the brakes but uses similar fluid.

A noise present only when the clutch pedal is depressed, stopping when released, most likely indicates a worn:

• a.Water pump bearing, which whines whenever the engine is running
• b.Release (throwout) bearing✓
• c.Pilot bearing, which instead is noisy with the transmission in gear
• d.Front wheel bearing, which drones and changes with vehicle speed

The release bearing spins only while the pedal is down and pressing on the pressure plate fingers, so noise that appears then points to it. A pilot bearing, by contrast, is noisy with the pedal down and the transmission in gear. Replacing the release bearing with the clutch is standard practice.

A flywheel with heat cracks or a worn friction surface should be:

• a.Left as-is as long as a brand-new clutch disc is being installed
• b.Painted over the cracked area to seal the heat checks in the metal
• c.Coated with high-temperature grease to smooth the worn surface
• d.Resurfaced or replaced during clutch service✓

A scored or heat-checked flywheel prevents proper clutch engagement and causes slipping or chatter, so it is machined or replaced when the clutch is done. Dual-mass flywheels are inspected for excessive play and usually replaced. A fresh surface ensures full disc contact.

A clunk heard shifting from Drive to Reverse or on throttle tip-in, with the transmission otherwise fine, often indicates:

• a.A clogged fuel filter restricting flow to the fuel injectors
• b.A broken or worn engine or transmission mount✓
• c.A worn oxygen sensor that has slowed its response in the exhaust
• d.A low brake fluid level in the master cylinder reservoir

A failed mount lets the powertrain shift on its supports, producing a clunk during gear and load changes. Inspecting the mounts for cracks and separation confirms it. Worn U-joints can cause a similar driveline clunk.

The transfer case in a four-wheel-drive vehicle is used to:

• a.Split engine power between the front and rear axles✓
• b.Filter the engine oil before it reaches the crankshaft main bearings
• c.Increase air conditioning system pressure during heavy cooling loads
• d.Charge the vehicle's battery through an internal gear-driven generator

The transfer case distributes torque to both axles and often provides a low range for extra reduction. Low fluid or worn chains and clutches cause noise or engagement problems. It is serviced with the specified fluid.

A limited-slip differential that chatters or shudders while turning slowly is often corrected by:

• a.Increasing the tire pressure well above the placard specification
• b.Adding the specified friction-modifier additive to the gear oil✓
• c.Replacing the wheel speed sensor mounted at the affected axle
• d.Adding a small amount of brake fluid directly into the axle housing

Clutch-type limited-slip units need a friction modifier so the plates release smoothly; without it, they grab and chatter in tight turns. Using the correct gear oil with additive cures it. Persistent noise may mean worn clutch plates.

When setting up a ring-and-pinion gear, the tooth contact pattern is checked to verify correct:

• a.Pinion depth and backlash✓
• b.Tire balance and radial runout across the drive wheels of the axle
• c.Brake fluid level within the master cylinder before the road test
• d.Ignition timing advance measured at the crankshaft position sensor

A marking-compound pattern on the ring gear teeth reveals whether pinion depth and backlash are correct before final assembly. An improper pattern causes whine and premature wear. Shims and adjusters are changed to center the pattern.

Gear oil leaking from an axle seal onto the brake can cause:

• a.A charging system fault that illuminates the battery warning lamp
• b.Contaminated linings and a brake pull or grab✓
• c.An evaporative emission leak code from the fuel vapor canister
• d.Higher engine oil pressure at idle and during cruising conditions

A leaking axle seal lets gear oil reach the brake shoes or pads, causing them to grab or the vehicle to pull. The seal must be replaced and the friction material cleaned or renewed. Ignoring it risks unsafe braking.

Many automatic transmissions route fluid through a cooler located in the:

• a.Air cleaner housing, where intake air blows across the fluid lines
• b.Fuel tank, where the cool fuel absorbs heat from the transmission
• c.Radiator, sometimes with a separate auxiliary cooler✓
• d.Exhaust manifold, using engine heat to warm the fluid when cold

ATF is cooled in a heat exchanger inside the radiator, sometimes with an added external cooler for heavy use, because heat is the main enemy of the fluid. A failed internal cooler can cross-contaminate coolant and ATF. Adequate cooling extends transmission life.

An automatic that shifts fine when cold but slips as it warms up most likely has:

• a.A clogged cabin air filter reducing airflow through the HVAC case
• b.A worn outer tie rod end introducing play into the steering
• c.A misadjusted parking brake dragging the rear brakes when warm
• d.Worn clutches or low pressure that worsen as fluid thins✓

As fluid warms and thins, marginal clutches or seals slip more, so a transmission that fails only when hot points to internal wear or low pressure. A pressure test at temperature helps confirm. Correct fluid level and condition are checked first.

A momentary rise in engine rpm during an upshift, with no matching increase in vehicle speed, is called:

• a.Engine braking felt when the driver lifts off the throttle downhill
• b.Shift flare (slippage during the shift)✓
• c.Converter lockup engaging the clutch to eliminate fluid slippage
• d.Torque multiplication produced by the converter during acceleration

Flare happens when the oncoming clutch or band applies too slowly and engine speed briefly runs up during the shift, indicating wear or low pressure. It stresses the friction elements. Diagnosis includes fluid condition, pressure, and solenoid operation.

A code for the torque converter clutch circuit (such as P0741) most often relates to:

• a.A worn front wheel bearing that drones and roughens with speed
• b.The TCC failing to lock up or slipping too much✓
• c.A leaking radiator cap venting coolant into the overflow bottle
• d.A faulty ABS wheel-speed sensor at one of the four wheels

This code sets when the module sees the converter clutch not achieving or holding lockup, from a stuck solenoid, worn clutch, or fluid issues. Persistent slip overheats the fluid. Checking the solenoid, fluid, and valve body is the next step.

A manual transmission that pops out of gear on its own most commonly indicates:

• a.Worn shift detents, synchronizers, or a broken mount✓
• b.A clogged fuel injector causing a lean misfire under acceleration
• c.A weak battery that cannot hold a full charge between road trips
• d.An overcharged air conditioning system raising the high-side pressure

Worn detent springs, damaged synchro teeth, or excessive powertrain movement from a bad mount let the gear disengage under load. Inspection of the linkage, internal parts, and mounts finds the cause. Continued use accelerates wear.

The correct way to remove air from a hydraulic clutch system is to:

• a.Bleed at the slave cylinder while keeping the reservoir full✓
• b.Pump the pedal until it firms up and then simply drive the vehicle
• c.Loosen the transmission mount to let the trapped air work its way out
• d.Add a heavier, thicker fluid so the trapped air cannot compress

Air makes the clutch hydraulic pedal soft and prevents full release, so the system is bled at the slave bleeder like a brake circuit while topping the reservoir. A gravity or pressure bleed removes trapped air. Then full disengagement returns.

A torn CV joint boot found during inspection should be addressed promptly because:

• a.It causes the alternator to overcharge and boil the battery dry
• b.It reduces engine oil pressure delivered to the crankshaft bearings
• c.It sets an evaporative emission leak code from the vapor canister
• d.Lost grease and entering dirt will quickly ruin the joint✓

Once the boot tears, grease flings out and grit gets in, wearing the joint until it clicks and fails. Replacing the boot early, before contamination, can save the joint. A neglected joint requires a full axle replacement.

A vehicle will not crank in Park but cranks in Neutral. The MOST likely cause is:

• a.A slipping torque converter that cannot transmit engine torque
• b.A leaking axle seal allowing gear oil to reach the brake linings
• c.A worn clutch disc slipping under load in the higher forward gears
• d.A faulty transmission range (neutral safety) switch✓

The range switch tells the starter circuit the vehicle is in Park or Neutral; when it is misadjusted or failing, starting may work in only one position. Adjusting or replacing the switch restores normal cranking. It also feeds gear position to the module.

A transmission fluid cooler line that leaks lowers the fluid level, which can lead to:

• a.Improved shift quality because less fluid means quicker apply
• b.A stronger clutch engagement as the fluid level slowly drops
• c.Higher fuel economy from reduced drag inside the transmission case
• d.Slipping, overheating, and internal damage✓

Low fluid from a leaking cooler line reduces pressure and cooling, causing slip and heat that damage the clutches. The line is repaired and the fluid refilled to the correct level. Prompt repair prevents costly failure.

An automatic transmission used for frequent trailer towing benefits most from:

• a.A higher-octane fuel to lower the transmission's operating temperature
• b.An auxiliary cooler to control fluid temperature✓
• c.A larger battery to supply the extra current the transmission draws
• d.A thicker grade of engine oil to reduce internal friction and heat

Towing loads the transmission and raises fluid temperature, so an auxiliary cooler keeps the ATF within a safe range and extends its life. Heat is the leading cause of transmission failure. Fluid condition should also be monitored under heavy use.

The vehicle speed sensor (VSS) signal is used by the transmission controller to:

• a.Control the air conditioning compressor clutch air gap and cycling
• b.Measure the oxygen content in the exhaust for fuel-trim correction
• c.Help determine shift timing and converter lockup✓
• d.Read the coolant level in the radiator and its overflow reservoir

The controller compares vehicle speed with throttle and load to schedule shifts and apply the converter clutch. A faulty VSS can cause erratic or no shifts and a speedometer fault. Its signal is verified with a scan tool.

In a continuously variable transmission (CVT), the ratio is changed by:

• a.Shifting between fixed planetary gearsets held by clutches and bands
• b.Varying the effective diameter of two belt-linked pulleys✓
• c.Engaging a series of dog clutches to select individual gear pairs
• d.Changing the final drive ring-and-pinion gear ratio on the fly

A CVT uses a steel belt or chain running between variable-width pulleys, so moving the pulley halves changes the ratio smoothly with no fixed steps. This keeps the engine near its most efficient speed. CVT fluid is a specific type not interchangeable with ATF.

Technician A says worn universal joints can cause a driveline clunk and vibration. Technician B says a bent or unbalanced driveshaft can cause a speed-related vibration. Who is correct?

• a.Both A and B✓
• b.Technician B only
• c.Neither A nor B
• d.Technician A only

Worn U-joints clunk and vibrate, and a bent or unbalanced shaft vibrates more as speed rises. Both technicians are correct. Inspecting the joints, runout, and balance isolates the source.

Technician A says overheated automatic transmission fluid turns dark and smells burnt. Technician B says burnt fluid indicates the friction material may be damaged. Who is correct?

• a.Neither A nor B
• b.Technician A only
• c.Technician B only
• d.Both A and B✓

Overheating darkens the fluid and produces a burnt odor, and that heat comes from slipping friction elements that are wearing. Both technicians are correct. Fluid condition is an important early diagnostic clue.