Your FREE ASE A3 Flashcards 2026 – 200+ Cards

The assembly that connects and disconnects engine power to a manual transmission; a pressure plate clamps a friction disc to the flywheel to transmit torque.

A heavy disc bolted to the crankshaft; its machined face is the friction surface the clutch disc clamps against, and it stores rotational energy to smooth power pulses.

The plate splined to the transmission input shaft, clamped between the flywheel and pressure plate, that transmits engine torque when engaged.

A spring-loaded cover assembly bolted to the flywheel; its diaphragm spring clamps the clutch disc, and pressing the release fingers unclamps it.

The cone-shaped spring in a pressure plate; its fingers are pushed by the release bearing to unclamp the disc, and it sets the clamping load.

Rides on the input-shaft hub and pushes the pressure plate's spring fingers when the pedal is pressed, disengaging the clutch; rattles in neutral with the pedal down when worn.

A small bearing or bushing in the crankshaft (or flywheel) that supports the front of the input shaft; makes noise only with the clutch released and the transmission in gear.

The lever that moves the release bearing toward the pressure plate, actuated by a cable or a hydraulic slave cylinder.

In a hydraulic clutch, the pedal-operated cylinder that generates hydraulic pressure and sends it to the slave cylinder.

Receives pressure from the master cylinder and converts it to mechanical force on the clutch fork or release bearing to disengage the clutch.

A clutch actuated by a cable from the pedal to the fork, rather than by hydraulic master and slave cylinders.

The small amount of pedal travel before the release bearing contacts the spring fingers; too little keeps the bearing loaded and causes slip and bearing wear.

Engine rpm rises but the vehicle doesn't accelerate to match; caused by worn or oil-soaked facings, a weak pressure plate, a glazed flywheel, or no free play.

A vibration felt during clutch take-up; caused by a glazed or oil-contaminated disc, a warped flywheel, or worn engine/transmission mounts.

Failure of the clutch to fully release, so the disc keeps spinning; causes grinding into several gears and hard shifting from a stop.

A two-piece flywheel with internal springs that damp drivetrain vibration; worn springs cause an idle rattle and a rocking sensation on start-up and shutdown.

The face (lateral) wobble of the flywheel measured with a dial indicator; excessive runout causes clutch chatter and may prevent full release, so resurface or replace.

Friction facings soaked with oil (often from a leaking rear main seal); the disc can't grip, so it must be replaced and the leak repaired before reassembly.

Noise present with the clutch released and the transmission in gear at a stop indicates the pilot bearing, because the input shaft and crankshaft turn at different speeds.

Noise in neutral with the pedal fully down indicates the release bearing, which is still spinning against the diaphragm-spring fingers.

A splined tool used to center the clutch disc on the flywheel pilot before tightening the pressure plate, so the input shaft can enter the disc and pilot bearing.

A clutch with a mechanism that automatically compensates for disc wear, keeping pedal free play and release point consistent.

A hardened, shiny friction surface caused by excess heat and slipping; reduces grip and causes shudder and slipping.

Setting cable or hydraulic free play so the clutch fully engages (no slip) and fully releases (no drag) within pedal travel.

Removing air from the master/slave system; air causes a soft pedal and incomplete release, so the system is bled until the pedal is firm.

Clearance that keeps the release bearing off the spring fingers when the pedal is up; loss of it loads the bearing and causes slip and premature wear.

Another name for the pressure plate: the cover, diaphragm (or coil) springs, and release levers that clamp the disc to the flywheel.

Machining the flywheel face flat and true when installing a new clutch, to remove glazing, heat checks, and runout.

Coil-spring (Long/Borg & Beck) types use multiple coil springs and release levers; diaphragm types use one cone spring and are more common today.

Indicates the clutch is not releasing (drag) — often from a warped disc, no free play, air in the hydraulics, or a binding pilot bearing.

The ball stud or pivot the clutch fork rocks on; a worn pivot causes erratic release and noise.

A switch/sensor that tells the engine controller the clutch is pressed (for starting and cruise control), and can affect start permission.

A hydraulic slave cylinder built around the input shaft that also serves as the release bearing; replaced as a unit when leaking.

A switch that only allows the starter to crank when the clutch pedal is fully depressed.

Wavy springs between the disc facings that cushion engagement; worn ones cause harsh, grabby take-up.

Coil springs in the disc hub that absorb torsional shock and reduce gear rattle; broken springs cause a rattling noise.

Judder is a vibration during engagement (contamination, glazing, mounts); slip is lost drive with rising rpm (worn facings, weak plate, no free play).

Gradual, moderate use of a new clutch to seat the friction surfaces; harsh early use can glaze or shock-load the disc.

A gearbox in which the driver selects gear ratios by hand, routing engine torque through pairs of meshing gears of different tooth counts.

Carries engine torque from the clutch into the transmission; it drives the countershaft and the constantly meshed speed gears.

Carries power from the input shaft up to the mainshaft speed gears, providing the gear pairs that create each ratio.

Carries the speed gears that the driver locks to it through synchronizers; delivers the selected ratio to the driveshaft or final drive.

Uses a friction-cone blocker ring to match a gear's speed to the sliding sleeve before the dog teeth engage, preventing clash.

The friction cone that rubs a gear's cone to equalize speeds during a shift; wear causes grinding into that one gear.

The sliding collar the shift fork moves; once speeds match, it slides over the gear's dog teeth to lock the gear to the shaft.

The teeth on a speed gear that the synchronizer sleeve engages; rounded dog teeth let a gear pop out under load.

A pronged component on a shift rail that straddles a synchronizer sleeve and slides it along the shaft to engage or disengage a gear.

The rod that the shift fork is mounted on; moved by the shifter, it carries the fork to engage a gear and is held by a detent.

A spring-loaded ball that seats in a notch on the shift rail to hold the rail in its selected position; a weak detent lets the transmission jump out of gear.

A mechanism that prevents two gears from engaging at once by locking the other shift rails when one is moved.

Driven (output) tooth count divided by drive (input) tooth count; a ratio above 1 is a reduction, below 1 is overdrive.

A gear ratio greater than 1:1 where the output turns slower than the input, multiplying torque (for example, first gear).

A gear ratio below 1:1 where the output turns faster than the input, lowering engine rpm for highway cruising.

When power passes through more than one gear pair, the overall ratio is the product of the stage ratios (multiply, don't add).

An extra gear inserted in the reverse power path to reverse output direction; many reverse gears are not synchronized, so a grind on reverse is common.

Gears with angled teeth that mesh gradually for quiet, strong operation; used for the constantly meshed speed gears in modern transmissions.

Gears with straight teeth; simpler and used for sliding reverse gears, but noisier than helical gears.

Points to a worn or cracked blocker ring (synchronizer) for that specific gear.

Points to a clutch that is not fully releasing (free-play, air, drag), keeping the input shaft spinning.

Points to a weak detent, worn shift forks, rounded dog teeth, excessive endplay, or worn engine/transmission mounts.

Points to clutch drag, a dragging pilot bearing, binding shift linkage, worn synchronizers, or cold/wrong-viscosity gear oil.

Points to the input shaft or countershaft bearing — parts turning at engine speed in neutral.

The axial (in-and-out) free movement of a shaft; excessive endplay lets gears partially disengage and causes noise and jump-out.

A controlled amount of load applied to a bearing (often via shims) so it has no play; set to specification on shafts and pinions.

Lubricant for manual gearboxes; API GL ratings indicate the EP additive level — use the manufacturer-specified viscosity and rating.

Wear points in the external shifter linkage; worn bushings cause sloppy or hard shifting and missed gears.

The housing that bolts the transmission to the engine and encloses the clutch and flywheel; misalignment causes release and noise problems.

The path torque takes through the engaged gears for a given gear selection; tracing it explains which parts are loaded in each gear.

The grooved coupling on a shaft (input shaft, axle, slip yoke) that transmits torque while allowing axial movement.

Supports the input shaft in the transmission case; when worn it whines in neutral with the engine running and clutch engaged.

A retaining ring that locates gears, bearings, or CV joints on a shaft or in a bore; used throughout drive-train assemblies.

A gearbox with no dipstick; fluid level is checked at a fill/check plug at the specified temperature and procedure.

The spring behind the detent ball; weakened, it lets the rail creep out of its notch so the transmission jumps out of gear.

A mechanism (ring or lift collar) that prevents accidental engagement of reverse while driving forward.

Locating dowels that center the transmission to the engine; misalignment causes input-shaft and release problems and bearing wear.

The hub splined to the shaft plus the spring-loaded keys (inserts) that push the blocker ring against the gear cone during a shift.

Whine usually rises and falls with the gears in mesh (load/speed), while a bearing produces a rougher growl that tracks the shaft's rotation.

A rubber mount that supports the rear of the transmission; when collapsed it changes driveline angle and causes vibration and clunks.

The grade (for example, 75W-90) specified for a gearbox or axle; using the wrong viscosity causes hard cold shifting or excess wear.

An ASE question format where you judge whether Technician A is correct, B is correct, both, or neither — read each statement as a separate claim.

A unit that combines the transmission, final drive, and differential in one housing, used in transverse front-wheel-drive vehicles.

A transaxle includes the differential and final drive in its case and drives two half-shafts; a transmission drives one shaft to a remote axle.

A fixed gear reduction between the transmission output and the differential; it multiplies torque and sets the overall ratio after the selected gear.

Parallel helical gears used in a transverse transaxle, since the engine and axles are already in line and power need not turn 90 degrees.

Transmits engine power from the clutch into the transaxle for gear selection.

The differential built into the transaxle case that splits drive to the two front half-shafts and lets the wheels turn at different speeds.

A drive shaft, fitted with CV joints, that delivers torque from the transaxle differential to a front wheel.

In a transaxle, points to the final-drive or differential gears, which turn with the axle shafts; the noise persists while coasting in neutral.

In a transaxle in neutral, points to the input shaft or its bearing.

Often points to worn CV joints on the half-shafts; inspect the boots and joints.

The housing that encloses and protects the gearsets, final drive, and differential of a transaxle.

The small gears in the differential case that mesh with the side gears, allowing the two driven wheels to turn at different speeds.

The gears splined to the axle shafts (or half-shafts); driven by the spider gears, they transmit torque to each wheel.

The large final-drive gear bolted to the differential case; driven by the final-drive pinion, it turns the whole differential assembly.

Rubber mounts that locate the transaxle and damp vibration; worn mounts cause clunks and can lead to gear jump-out.

The plunging inboard joint on a half-shaft that absorbs length change as the suspension moves while transmitting torque to the transaxle.

The fixed (Rzeppa, ball-type) joint at the wheel end of a half-shaft that allows steering angle while delivering constant-velocity torque.

Verifying gear-oil level via the fill/check plug; low fluid causes whine, hard shifting, and premature gear and bearing wear.

Often a synchronizer issue; inspect the blocker rings and shift mechanism, and confirm clutch release and fluid condition.

An engine mounted sideways so the crankshaft is parallel to the axles; pairs naturally with a transaxle in front-wheel drive.

The shaft that carries torque from the transmission to the rear axle in a rear- or four-wheel-drive vehicle, fitted with universal joints.

A cross-and-bearing (Cardan) joint that lets a driveshaft transmit torque through small angle changes; output speed fluctuates at angle, so joints are paired.

A splined yoke at the front of a driveshaft that slides in and out of the transmission to accommodate length change from suspension movement.

A joint that delivers a constant output speed through large, changing angles, used on FWD and independent-rear half-shafts.

A ball-and-cage outer CV joint that allows large steering angles while transmitting torque at constant velocity.

A plunging inner CV joint using three rollers on a spider, allowing the half-shaft to change length as the suspension moves.

The flexible rubber cover that retains grease and keeps dirt out of a CV joint; a torn boot is the leading cause of CV-joint failure.

The classic sign of a worn outer CV joint on a front-wheel-drive vehicle.

Often a worn inner (plunging) CV joint, or a worn U-joint on a rear-wheel-drive driveshaft.

Points to a worn or binding U-joint, a bent or unbalanced driveshaft, or an incorrect driveline angle.

Balance weights keep a spinning driveshaft from vibrating; lost weights or built-up undercoating cause a speed-related vibration.

The working angle of the U-joints set by the transmission and pinion positions; an incorrect angle causes vibration and accelerated U-joint wear.

A rubber-mounted bearing supporting a two-piece driveshaft at its midpoint; when worn it causes vibration and a clunk.

A CV joint keeps output speed constant through large angles; a U-joint's output fluctuates at angle, so U-joints are paired to cancel it.

The forked driveshaft end that holds a U-joint cross; a slip yoke also allows length change, while a flange yoke bolts to a companion flange.

The flange on the differential pinion (or transmission) that the driveshaft yoke bolts to.

Aligning the two U-joint yokes on a driveshaft in the same plane so their speed fluctuations cancel; out-of-phase joints cause vibration.

Service step to replace a CV joint or boot; the hub nut and joints are freed so the shaft can be pulled from the transaxle.

Pressing out the old cross and bearing caps and installing new ones; checked for binding so the joint moves freely after assembly.

Special joint grease packed into CV joints and serviceable U-joints; loss of grease through a torn boot leads to wear and noise.

Radial wobble of the driveshaft measured with a dial indicator; excessive runout (bent shaft) causes a speed-related vibration.

A stiff spot in a universal joint from worn or dry needle bearings; causes vibration and accelerates failure.

The small roller bearings in each U-joint bearing cap that let the cross pivot; loss of grease leads to wear and a clunk.

The in-and-out movement an inner tripod CV joint allows so the half-shaft length can change with suspension travel.

Wobble at the pinion flange that contributes to driveshaft vibration; checked when diagnosing a speed-related rear-axle vibration.

Unequal-length half-shafts (or an intermediate shaft) used to balance the layout and reduce torque steer in front-wheel drive.

A short shaft and support bearing between the transaxle and one front half-shaft, used to equalize shaft lengths.

The band that secures a CV boot to the shaft and joint; a loose or failed clamp lets grease escape and the joint fail.

Another name for a conventional universal (U) joint, named for its cross-and-bearing design.

Two U-joints with a centering ball at one end of a driveshaft, used at steep angles to give near-constant velocity.

The assembly that delivers torque to the wheels through the ring-and-pinion final drive and the differential.

A gear set that splits torque between two drive wheels while allowing them to rotate at different speeds, as needed when cornering.

The final-drive gear set in a drive axle: the pinion drives the larger ring gear, setting the axle ratio and turning power to the axle shafts.

A bevel ring-and-pinion with the pinion offset below the ring-gear centerline; turns driveshaft power 90 degrees and needs extreme-pressure (EP) gear lube.

The ring-gear teeth divided by the pinion teeth (for example, 3.73:1); a numerically higher ratio gives more torque but higher engine rpm.

The clearance between the meshing teeth of the ring and pinion; set to specification, it prevents binding and gear noise.

How far the pinion is set into mesh with the ring gear, adjusted by shims; wrong depth produces an incorrect contact pattern and gear howl.

The marking compound pattern on the ring-gear teeth used to verify correct pinion depth and backlash during a differential setup.

The controlled load on the pinion bearings, set by a crush sleeve or shims; too little allows play and noise, too much overheats the bearings.

A spacer between the pinion bearings that is crushed to set pinion bearing preload; replaced whenever the pinion nut is loosened.

A standard differential that sends equal torque to both wheels but spins the wheel with the least traction.

Uses clutches, cones, or gears to resist a large wheel-speed difference, biasing torque to the wheel with traction.

A differential that can lock both axle shafts to turn together for maximum traction in low-grip conditions.

An additive required by many clutch-type limited-slip differentials to prevent chatter and clunk during slow turns.

The gears splined to the axle shafts; driven by the spider gears, they deliver torque to each wheel.

The small gears on the cross shaft inside the differential case that mesh with the side gears to allow different wheel speeds.

The shaft that carries torque from the differential side gear to a drive wheel; supported by bearings in the axle housing.

A rear axle retained inside the differential by a C-shaped clip; the differential must be opened to remove the axle shaft.

A rear axle held by a pressed-on bearing and retainer plate at the housing end, removed without opening the differential.

The in-and-out free movement of the axle shaft; set to spec by shims or the bearing design to prevent noise and seal wear.

The seal around the pinion at the companion flange; a leak shows as gear-oil at the front of the differential and can lower fluid level.

The seal at the end of the axle housing that keeps gear oil in and contaminants out; a leak can soak the brakes.

Points to worn ring and pinion or incorrect backlash/preload in the drive axle.

Points to excessive backlash or worn side/spider gears in the differential.

Points to the wrong fluid or a missing limited-slip friction-modifier additive.

Points to an incorrect pinion depth or gear-tooth contact pattern.

The housing that holds the spider and side gears and to which the ring gear bolts; it rotates with the ring gear.

Extreme-pressure gear oil required for hypoid axles because of the high sliding tooth contact between ring and pinion.

Adjusting side shims or bearing adjusters to move the ring gear, achieving the specified ring-and-pinion backlash.

The drive side carries torque under power, the coast side under deceleration; the contact pattern is read on both during setup.

Limited-slip clutch packs run in gear oil (wet); the friction-modifier additive in that oil controls their engagement and prevents chatter.

A common trade name for a clutch-type limited-slip differential that drives both wheels for added traction.

A flat bearing surface that controls axial play and carries thrust loads between rotating gears or the differential side gears.

The shaft (pin) the spider gears ride on inside the differential case, retained by a pin or bolt.

Gear-marking paste applied to ring-gear teeth to reveal the contact pattern when setting up a differential.

A growl or rumble that changes with load (lifting on a curve loads the opposite bearing) and tracks vehicle speed; indicates a worn axle bearing.

The load on the carrier (side) bearings set by shims or adjusters; correct preload keeps the ring gear stable under load.

The casing that holds the differential, axle shafts, and bearings, and contains the gear oil in a solid drive axle.

A drain plug with a magnet that captures metal particles; heavy metal on it signals internal gear or bearing wear.

The set load on tapered axle/pinion bearings; correct preload prevents both looseness (noise) and overheating.

Pinion bearing preload is set either by a collapsible crush sleeve or by selectable shims with a solid spacer, depending on axle design.

The point in an axle line where a different carrier case is needed to accommodate certain ratio ranges of ring gear.

Found by counting ring and pinion teeth, by a tag/code, or by turning the input one revolution and counting wheel turns.

The two parts of a tapered roller bearing: the cup (outer race) pressed in the housing and the cone (rollers + inner race) on the shaft.

Spring wrap that lets the axle rotate slightly under hard acceleration; can cause hop and U-joint angle change.

A system, usually with a transfer case and high/low ranges, that drives all four wheels; often part-time and intended for low-traction use.

A full-time system that drives all four wheels through a center differential or coupling, so it can stay engaged on dry pavement.

The gearbox in a 4WD vehicle that sends power to both front and rear axles and provides high and low gear ranges.

A transfer-case gear range that multiplies torque for off-road, towing, or steep grades at low speed.

The normal transfer-case range used for everyday on-road driving in a 4WD vehicle.

A system that locks the front and rear axles together with no center differential; must be used only on loose or slippery surfaces.

A system with a center differential or viscous coupling that allows a front-to-rear speed difference, so it can run on dry roads.

A differential between the front and rear drivelines that lets the axles turn at different speeds, preventing driveline wind-up in AWD.

The torque bind (crow-hop) when part-time 4WD is engaged on a high-traction surface, because the locked axles can't turn at different speeds in a turn.

A silicone-fluid clutch that transfers torque between front and rear when a speed difference develops; common in AWD systems.

Front-hub devices on some part-time 4WD vehicles that connect or disconnect the front wheels from the axle shafts to save wear and fuel in 2WD.

A chain inside many transfer cases that transfers power to the front output shaft; a worn chain causes noise and slack.

A 4WD feature allowing engagement between 2WD and 4WD high while moving, via electric or vacuum actuation.

The differential in the front axle of a 4WD/AWD vehicle that splits torque to the front wheels and allows them different speeds.

The shaft that carries power from the transfer case to the front differential in a 4WD vehicle.

Normal driveline wind-up when part-time 4WD is engaged on high-traction surfaces — disengage 4WD, not a component failure.

Check the shift actuator (vacuum/electric), the transfer-case linkage, the front-axle disconnect or locking hubs, and the control module.

The lubricant specified for the transfer case (gear oil or ATF, per the maker); low or wrong fluid causes noise and chain/gear wear.

A limited-slip biases torque smoothly to the wheel with grip; a locking differential rigidly locks both wheels to turn together for maximum traction.

A mechanism that disconnects the front axle shaft in 2WD on some 4WD vehicles to reduce drag and wear, reconnecting when 4WD is selected.

An AWD system that uses an electronically controlled clutch to send torque to the secondary axle only when wheel slip is detected.

A 4WD engagement system that uses engine vacuum to shift the transfer case or front-axle disconnect; vacuum leaks cause non-engagement.

A transfer case shifted by an electric motor/encoder under control-module command; faults set codes and prevent range changes.

A viscous coupling transfers torque on slip with no mechanical lock; a center differential always allows a controlled front-to-rear speed difference.

All tires must be matched in size and wear; mismatched tires create constant speed differences that bind the driveline and damage couplings.