Transmission, Driveline, Steering and Suspension Systems
Domain 5: Transmission, Driveline, Steering and Suspension Systems
This domain covers how drive reaches the wheels and how the vehicle steers and rides. The exam tests component identification, inspection, lubrication, alignment and fault symptoms.
Core rules
- Manual transmission uses a clutch to connect and disconnect engine torque. Check clutch pedal free play, release point and hydraulic condition.
- Automatic transmissions use a torque converter and hydraulic control. Use only the specified ATF; level checks often require a particular temperature and engine state.
- Driveline components include driveshafts, universal joints, CV joints, differentials and wheel bearings. A split CV boot loses grease and admits dirt; replace or rebuild promptly.
- Steering systems include rack-and-pinion, tie rods and power assistance. Check for play, leaks and boot damage.
- Wheel alignment angles: camber is vertical tilt, caster is steering-axis tilt, toe is the difference in front and rear of the wheels. Incorrect toe usually feathers tyre tread.
- Suspension includes springs, dampers, struts, ball joints and bushings. Tighten rubber bushings at normal ride height unless the procedure says otherwise.
Worked example
A car vibrates at 80-100 km/h, and the steering wheel shakes. The vibration is speed-related, not engine-related. Reasoning: check tyre pressure, tread and wheel balance first; a lost wheel weight or bent rim is common. If the vibration appears under acceleration and fades on overrun, inspect CV joints and driveshafts. If it appears after hitting a kerb, check alignment and bent suspension parts.
Traps
- Mixing ATF specifications.
- Diagnosing a CV joint knock as an engine mount without inspection.
- Tightening suspension bushes with the vehicle hanging.
- Ignoring a torn steering rack boot.
- Setting toe without checking steering wheel centre and camber/caster.