How Does a Clutch Work?
At its most basic, when the clutch pedal is pressed the engine and transmission are disconnected, so you can safely change gear or stop the car without the engine stalling.
The most common type of clutch is the dry-plate friction clutch. This type is used in most of the Toyota 4x4s that we support. This system consists of the flywheel, and pressure plate with the clutch disc (or single friction plate) being sandwiched between the two and a release bearing. They are located inside the bell housing assembly.
  • Flywheel - This is attached to the engine's crank so that whenever the engine is on, it is always rotating. It provides mass for rotational inertia to keep your engine running. The clutch is bolted to the flywheel.
  • Clutch plate - It is designed to create friction between the flywheel, itself and the pressure plate.
  • Pressure Plate - It is bolted to the flywheel, with the clutch plate in between, so that it spins when the flywheel and engine spin. The pressure plate is designed to clamp the clutch plate in place whenever the clutch pedal is disengaged (when the pedal is released).
  • Release/Thrust Bearing - Designed to contact the diaphragm when the clutch pedal is operated.
The diagram below shows how all the clutch parts work when your pedal is either engaged or disengaged.

Symptoms of a Faulty Clutch
Here are some Clutch related issues and problems to look out for. This information has been provided by Aisin who manufacture our clutches.
1. SLIPPING RELATED PROBLEMS
CONDITION: Oil or similar substance is on the friction surface of the facings.
CAUSE:
  1. Transmission oil or engine oil has leaked onto the facings.
  2. Insufficient verification at the time of installation.
  3. Problem with vehicle.
CURE:
  1. Inspect and repair transmission and/or engine.
  2. Replace disc with new part.
CONDITION: Facings are worn.
CAUSE:
  1. Facings have reached the end of its wear life.
  2. Facings have been scorched due to excessive partial clutch engagement, excessive 2nd gear starts, or excessive downshifting, etc.
  3. Improper driving method.
CURE:
  1. Improve driving method.
  2. Replace disc and cover with new parts.
CONDITION: Facings have broken.
CAUSE:
  1. Facings have burst due to rapid change in torque (i.e.: mis-shifting or speed shifting).
  2. Vehicle was driven with scorched facings.
  3. Improper driving method.
CURE:
  1. Improve driving method.
  2. Replace disc and cover with new parts.
CONDITION: Pressure of the diaphragm spring is weak.
CAUSE:
  1. Spring function of the diaphragm spring has degraded due to heat fatigue.
  2. Wrong part was installed.
  3. Improper driving method.
CURE:
  1. Improve driving method.
  2. Replace cover with correct part.
  3. Replace disc and cover with new parts.
CONDITION: Misalignment or malfunction in the release mechanism.
CAUSE:
  1. Release bearing remains connected to the diaphragm spring (partial engagement). (Cable tension changes with use, making the clutch more susceptible to slipping.)
  2. Misalignment at time of installation.
CURE: Readjust the release mechanism.
2. CLUTCH DRAG RELATED PROBLEMS
CONDITION: Splines are scratched, dented, or damaged.
CAUSE:
  1. Input shaft was scratched or other damage occurred to the splines when installing the transmission, resulting in sliding problems or a deformed disc plate, causing significant runout.
  2. Installation error.
CURE:
  1. Replace disc and cover with new parts.
  2. Ensure centering when installing transmission.
CONDITION: No grease on splines.
CAUSE:
  1. Grease was not applied or insufficiently applied when installing the clutch disc, resulting in sliding problems.
  2. Installation error.
CURE: Apply grease to the disc splines.
CONDITION: Deformed clutch disc.
CAUSE:
  1. Misalignment of the crankshaft and input shaft caused a wobble in the rotation (figure-8 rotation), deforming the disc so that power is transmitted even when disengaged.
  2. Installation error.
CURE:
  1. Replace disc and cover with new parts.
  2. Ensure centering when installing transmission.
CONDITION: Straps or other components are deformed.
CAUSE:
  1. Strap has been deformed or the retractable spring has been broken due to dropping the part.
  2. Damaged in shipping.
  3. Mishandling or installation error.
CURE: Replace cover with new part.
CONDITION: Release mechanism misaligned or failed.
CAUSE:
  1. Insufficient fluid (leaks, etc.) in clutch hydraulic parts.
  2. Incorrect cable adjustment.
  3. Release fork was installed incorrectly.
  4. Misalignment at time of installation.
CURE: Readjust the release mechanism.
CONDITION: Excessive run-out on flywheel.
CAUSE: Installation error.
CURE: Realign or replace the flywheel.
3. SHUDDERING AND CHATTERING PROBLEMS (Clutch Mechanism Failure and Abnormal Friction Surface)
CONDITION: Oil or similar substance is on the friction surface of the facings.
CAUSE:
  1. Facing was touched with oily hands when replacing the part.
  2. Excess spline grease was thrown onto the facing due to centrifugal force.
  3. Improper installation.
CURE:
  1. Replace disc with new part.
  2. Do not contaminate facing with oil.
CONDITION: The friction surface of the facings is showing heat degradation.
CAUSE:
  1. Facing has reached the end of its wear life.
  2. Facing has been scorched due to excessive partial clutch engagement, excessive 2nd gear starts, or excessive downshifting, etc.
  3. Improper driving method.
CURE:
  1. Replace disc and cover with new parts.
  2. Improve driving method.
CONDITION: Abnormality seen in the friction surface of the pressure plate.
CAUSE:
  1. Friction surface of the pressure plate has become glazed.
  2. Installation error.
  3. Improper driving method.
CURE:
  1. Replace cover with new part.
  2. Replace clutch cover when replacing disc.
  3. Improve driving method.
CONDITION: Abnormality seen in the friction surface of the flywheel.
CAUSE:
  1. Friction surface of the flywheel has become glazed.
  2. Installation error.
  3. Improper driving method.
CURE:
  1. Replace flywheel.
  2. Inspect and service flywheel when necessary.
  3. Improve driving method
4. ABNORMAL NOISES AND INABILITY TO DRIVE (Broken Clutch)
CONDITION: (1) Broken disc component.
CAUSE:
  1. Misalignment of the crankshaft and input shaft or other problem caused disc breakage, ejecting springs and other components.
  2. Installation error.
CURE:
  1. Replace disc and cover with new parts.
  2. Ensure centering when installing the transmission.
CONDITION: (2) Broken disc component.
CAUSE:
  1. Misalignment caused disc to break and engine power is not being transmitted.
  2. Installation error.
CURE: Replace disc and cover with new parts.
CONDITION: (3) Broken disc component.
CAUSE:
  1. Excessive partial clutch engagement or mis-shifting caused the facing to burst.
  2. Improper driving method.
CURE: Improve driving method.
CONDITION: A cover component has broken.
CAUSE:
  1. Significant run-out on the flywheel broke the cover’s retracting spring.
  2. Improper installation.
CURE: Replace flywheel with new part.
CONDITION: The edge of the diaphragm spring shows abnormal wear.
CAUSE:
  1. Misalignment of the crankshaft and input shaft or the bearing caused the edge of the diaphragm spring to wear, preventing smooth rotation of the bearing.
  2. Installation error.
CURE:
  1. Replace cover with new part.
  2. Ensure centering of the bearing.
5. CLUTCH COVER SELECTION ERRORS AND CLUTCH MECHANISM OPERATION FAILURES
CONDITION: Incorrect part number was installed.
CAUSE:
  1. Wrong part was installed.
  2. Incorrect part number selection.
CURE: Replace cover with the correct part.
CONDITION: Malfunction of the release mechanism is causing sliding resistance.
CAUSE:
  1. Resistance is causing rough movement of the release fork, installation rod, or cable.
  2. Installation error.
CURE: Readjust the release mechanism.
Note: This information has been provided by Aisin. The full PDF is downloadable on the Downloads tab within the Clutches on our website.

Clutch Adjustment Tips

When fitting a new clutch component, clutch adjustment maybe required. Many technicians believe the Hilux Pickups, Hilux Surfs & Land Cruisers have a hydraulic clutch system where there is no clutch adjustment, this is incorrect. They do have clutch adjustment and are adjustable.

> Download our Clutch Adjustment Guide here

Aisin - The Original Manufacturer of Toyota Clutches

All our clutches are supplied by Aisin. RoughTrax are authorized dealers of Aisin products, and have been since 2014.
  • Aisin are renowned worldwide for quality and reliability 
  • Original manufacturers of clutch components for Toyota. Engineered to the exact OE specifications as per the original fitment.
  • Exceptional clutch kit at a fraction of the original cost. 
  • Aisin Clutch Kits combines ideal clutch components to deliver optimal drivetrain efficiency. Providing ideal power transfer with precise pedal feel
  • Higher load capacity, achieved by the latest designs enables an increase in vehicle application.
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RoughTrax Parts

RoughTrax stock a wide range of clutch and related parts including:

Clutch Kits

Flywheels

Solid Flywheel Conversion

Master and Slave Cylinders

Clutch Release Fork

Clutch Bearings and Seals

> View all our Clutch Parts