Drivetrain and Axles
6 LessonsDriveshafts, differentials, CV axles, and 4WD/AWD systems explained.
Overview
The drivetrain delivers power from the transmission to the wheels. This module covers driveshafts, U-joints, CV axles, differentials, transfer cases, and the various configurations (FWD, RWD, AWD, 4WD) found in modern vehicles.
Key Components
- Driveshaft and U-joints
- CV axles and boots
- Differential and ring/pinion
- Transfer case (4WD/AWD)
- Wheel hubs and bearings
How It Works
Power flows from the transmission output shaft through the driveshaft (RWD) or CV axles (FWD) to the differential, which splits power between the drive wheels while allowing them to turn at different speeds in corners. 4WD and AWD add a transfer case to distribute power to all four wheels.
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Join the Nation — FreeCommon Problems
- CV axle boot tear causing joint failure
- U-joint wear causing vibration or clunk
- Differential whine from worn bearings
- Transfer case fluid neglect causing binding
- Wheel bearing noise and play
Diagnostic Tips
- CV axle click on turns = outer joint, vibration = inner joint
- U-joint check: grab driveshaft and rock it — any play is too much
- Differential noise changes with load (coast vs. drive)
- AWD fluid service is critical — all four corners must match
Related Systems
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