Which statement describes the universal joint's main function?

• A. To lock two shafts together
• B. To transmit torque
• C. To allow correct driveline geometry
• D. To transfer coolant

Answer: (C)

The universal joint is used to connect two drive shafts that aren’t in a straight line and to let them bend as the vehicle moves while still transmitting rotational power. That bending capability is essential because the suspension, steering, and engine angles change constantly, and the driveline must stay aligned so power continues to reach the wheels. In this sense, its main function is to preserve correct driveline geometry during movement. It does transmit torque, but the key point is enabling angular displacement without losing proper alignment. It doesn’t transfer coolant, and it isn’t merely a locking device.