Transmission, Clutch and Driveline
What this domain tests
This domain tests how torque travels from the engine to the road: clutch operation, manual gearbox internals, propeller shaft and universal joints, final drive, differential, and drive shafts. Expect questions on clutch free play, synchroniser function, gear ratio calculations, lubrication checks, and driveline noises.
Core rules
- The clutch friction disc is fitted with the marked side facing the flywheel; a reversed disc will not release and the vehicle will drag in gear.
- Pedal free play is typically 10-20 mm. Hydraulic clutches are bled from the slave cylinder until no air bubbles appear.
- Synchroniser rings match gear speeds; worn rings cause crunching on downshift. Never force a gear.
- Gear oil is checked at the filler/level plug with the vehicle level; it should be level with the hole, not above it.
- Automatic transmission fluid is checked warm, engine running, in Park or Neutral as specified, after cycling the selector.
- Universal joints must be phased correctly; incorrect phasing produces vibration that rises with road speed.
Worked example
Engine speed 3000 rpm, fourth gear 1.00:1, final drive 4.11:1, tyre rolling circumference 2.0 m. Wheel speed = 3000 ÷ 4.11 = 730 rpm. Distance per minute = 730 × 2.0 = 1460 m, which is 1.46 km per minute, or about 88 km/h. The reasoning is engine speed divided by total reduction, then multiplied by rolling circumference.
Traps that cost marks
- Fitting the clutch plate backwards, then blaming the hydraulics.
- Mixing ATF types or overfilling an automatic.
- Overfilling a manual gearbox past the level plug, which blows seals.
- Ignoring a split CV boot until the joint fails.