On rear-wheel-drive vehicles, a clunk when you put the vehicle in gear or let off the gas means U-joints with
excessive play. On front-wheel-drive vehicles, you’ll notice a clicking noise as you turn sharply, or a spatter
of oil on the back of the front wheels, which typically means a bad axle shaft. Shop our selection of drive
shafts and axles to get started on your vehicle repairs.
A rear-wheel-drive (RWD) vehicle will feature U-joints at the front and rear of the driveshaft, allowing for
some flexibility as the vehicle goes over bumps and road irregularities. Front-wheel-drive (FWD) vehicles
are designed with constant-velocity (CV) joints for the same purpose - these linkages use ball bearings in
tracks inside a cup-and-ball setup, so the axle shafts can accommodate the up-and-down movements of the
U-joints and CV joints will typically last the life of the vehicle - but not always. In the case of a RWD
vehicle, signs of worn U-joints include a noticeable clunk when putting the vehicle in gear, letting off the
throttle or accelerating. In extreme cases, you might notice vibration through the floorboard and seat. On a
FWD vehicle, worn CV joints will make a clicking, ratcheting sound that is noticeable during a tight turn.
You may also feel clunks and vibration. CV joints are more prone to failure, as the linkage is covered by a
rubber bellows-style boot that can tear and let in road grit or moisture, accelerating wear. If the boot is
torn, you might also notice a spatter of oil on the inside of the wheels.