Drive Shaft
A rotating steel tube that transmits engine torque from the transmission or transfer case to the differential.
A drive shaft (also called a propeller shaft) is a long, rotating steel or aluminum tube that transmits torque from the transmission or transfer case to the front or rear differentials. It is the primary power conduit in rear-wheel-drive, four-wheel-drive, and all-wheel-drive vehicles.
Because the vehicle's suspension moves up and down over road bumps, the differential moves relative to the transmission. To accommodate this movement, drive shafts utilize **universal joints (U-joints)** on each end, which allow the shaft to rotate smoothly at changing angles. A sliding slip yoke allows the shaft to adjust its length as the suspension travels.
Drive shafts are balanced to spin at high speeds with zero vibration. If a drive shaft is bent, dented, or throws a balance weight, it will produce a severe vibration that increases with vehicle speed.
The most common failure points are the U-joints, which can dry out, wear, or break. Symptoms of worn U-joints include a squeaking noise at low speeds, a loud clunk when shifting into drive or reverse, and high-speed vibrations. A broken drive shaft can detach while driving, causing catastrophic damage or a crash.