Transmission & Drivetrain Systems Flashcards

Which symptom most specifically indicates a worn or failing torque converter clutch (TCC) solenoid?

Answer: Shudder at light throttle around 40-50 mph during TCC lockup

A faulty TCC solenoid causes the lockup clutch to apply or release erratically, creating a characteristic shudder felt at light throttle near the lockup engagement speed.

In a 4WD system using manual locking hubs, what is the purpose of the locking hub?

Answer: It mechanically connects the front wheel to the front axle shaft to allow 4WD power transfer

When locked, the hub couples the wheel to the axle shaft so torque from the transfer case can drive the front wheels; when unlocked, the axle shaft spins freely to reduce parasitic drag.

Which gear in a final drive assembly is responsible for transmitting torque at 90 degrees from the driveshaft to the axle shafts?

Answer: Hypoid ring and pinion gear set

The hypoid ring and pinion redirects driveshaft torque 90 degrees to the axle shafts while also providing a final gear reduction ratio.

What is the primary reason automatic transmission fluid (ATF) specifications (e.g., Dexron, Mercon, SP-IV) must be matched to the transmission?

Answer: Each ATF formulation has specific friction modifiers that calibrate clutch engagement feel and shift quality

Friction modifiers in ATF are engineered to match the clutch materials in a specific transmission; using the wrong fluid alters shift feel and can cause shudder, slipping, or damage.

A rear-wheel drive vehicle with a worn carrier bearing (center support bearing) on a two-piece driveshaft will most likely exhibit:

Answer: A droning or vibration that changes with vehicle speed and may worsen under load

A failing center support bearing allows the driveshaft to wobble and vibrate at speeds proportional to shaft rotation, often worsening under load or torque.

During a transmission fluid exchange, a technician notices metal particles in the fluid pan. The MOST appropriate next step is to:

Answer: Inspect the transmission internally for damaged clutch packs, bearings, or planetary components before returning to service

Metal particles indicate internal wear or damage; continuing to operate the transmission without diagnosis risks catastrophic failure.

Which component prevents a vehicle from being started in any gear except Park or Neutral in an automatic transmission-equipped vehicle?

Answer: Neutral safety switch (transmission range sensor)

The neutral safety switch (or transmission range sensor) interrupts the starter circuit unless the transmission is in Park or Neutral, preventing unintended movement on start.