Differential Diagnosis and Repair
The differential assembly uses a conventional ring and pinion gear set to transmit the driving force of the engine to the wheels. The open differential allows the wheels to turn at different rates of speed while the axle transmits driving force. This prevents tire scuffing when going around corners and premature wear on internal axle components. Open differentials deliver equal torque to both wheels at all times. When a vehicle is equipped with a standard differential when one tire slips the other wheel does not receive enough torque to move the vehicle. To correct this condition, most manufacturers us a limited-slip differential (LSD).
Many models of all-wheel drive (AWD) vehicles on the road today use a viscous coupled limited-slip differential. The design uses a series of closely positioned plates, which do not physically touch each other. The plates are housed in a sealed chamber, which is filled with a thick and viscous silicone-based fluid. The silicone allows normal speed differences between two shafts, resisting high-speed differences associated with wheel slip/spin.
The differential clutch is bolted to the front of the limited-slip differential. The propeller shaft is connected to the front of the differential clutch. The differential clutch is connected directly to the limited slip differential pinion by a splined shaft. The differential clutch controls the degree of drive torque distributed to the rear wheels. A hydraulically controlled multi-disc clutch is used to vary drive torque.
Some conditions that warrant a drivetrain inspection are:
- Noisy When Coasting
- Intermittent Noise
- Constant Noise
- Noise on Turns