Which part of a vehicle's drivetrain allows the wheels to rotate at different speeds when turning?

The differential is a crucial component of a vehicle's drivetrain that allows the wheels to rotate at different speeds, particularly during turns. When a vehicle turns, the outer wheels travel a longer distance than the inner wheels. The differential enables this variation in wheel speed by splitting the engine torque and allowing each wheel to rotate independently as needed.

In essence, when a vehicle is cornering, the differential's design helps manage the differences in distance and speed between the left and right wheels. This function is essential for maintaining traction and stability during turns, helping to prevent skidding and improving overall vehicle handling.

Other components like the transmission, drive shaft, and transfer case each have their own specific roles. The transmission is responsible for controlling the power and speed delivered to the wheels, the drive shaft connects the transmission to the differential, and the transfer case typically divides power between the front and rear axles in four-wheel-drive vehicles. However, none of these components specifically manage the need for varying wheel speeds during turns the way the differential does.