A CV joint, or Constant Velocity joint, is a crucial component of a vehicle’s drivetrain that allows power to be transmitted from the engine to the wheels while accommodating the up-and-down motion of the suspension and the turning of the wheels. CV joints are most commonly found on front-wheel-drive and all-wheel-drive vehicles, although they can also be used in rear-wheel-drive setups.

CV joints are designed to maintain a constant velocity, which means they can transmit power smoothly even when the angle between the transmission and the wheels changes, such as during turns. This is important because the wheels on a vehicle need to rotate at different speeds when turning to maintain traction and stability.

There are two primary types of CV joints:

1. Rzeppa Joint (Outboard CV Joint): This type of CV joint is often used on the outer ends of the drive axles, connecting them to the wheel hub. It consists of a spherical outer housing with six ball bearings inside it. The inner race of the joint is connected to the transmission or differential, and the outer race is connected to the wheel hub. The balls allow the joint to flex and maintain constant velocity during turns.
2. Tripod Joint (Inboard CV Joint): Tripod joints are often used on the inner ends of the drive axles, connecting them to the differential or transmission. They have a three-lobed housing that fits into a three-lobed receiver in the transmission or differential. These joints are designed to allow for smooth movement at various angles.

CV joints are crucial for the efficient transfer of power and torque from the engine to the wheels, and they are subjected to a significant amount of stress during operation. Over time, CV joints can wear out or become damaged, leading to symptoms like clicking or popping noises when turning, vibrations, and loss of power. Regular maintenance and inspection of CV joints are essential to ensure the safe and efficient operation of a vehicle.