CV joints: signs they are dying and what a replacement costs
A failing CV joint usually announces itself with a clicking noise on tight turns. Here is how to confirm it, how long you can drive on one, and what fixing it costs.
A constant-velocity joint (CV joint) connects your drive axle to the wheel hub while letting the angle change as the suspension moves. When one starts to fail, the giveaway is a rhythmic clicking or knocking sound during slow tight turns, loudest on the side that is on the outside of the corner. Catch it early and you replace a boot. Catch it late and you replace the whole axle, plus possibly the wheel bearing.
Where the CV joints live on your car
Most front-wheel-drive cars have two CV joints per drive axle: an outer joint (next to the wheel) and an inner joint (next to the transmission). All-wheel-drive vehicles add a CV joint setup at each rear wheel. Rear-wheel-drive cars with independent rear suspension also use them at the rear axles. Trucks with solid rear axles do not have rear CV joints.
Each joint is filled with grease and sealed by a rubber boot. Boots crack with age, grease escapes, road grit gets in, the joint wears, the clicking starts.
How to tell which joint is failing
| Symptom | Joint location | What is happening |
|---|---|---|
| Click click click on slow tight turns | Outer joint, side opposite the turn | Worn ball tracks, grease starved |
| Vibration under acceleration | Inner joint | Plunge joint binding or worn |
| Grease sling across the inside of the wheel | Either, but most often outer | Boot is torn, grease centrifuged out |
| Clunk when shifting from drive to reverse | Inner joint, often paired with worn engine mounts | Worn splines or excessive endplay |
| Steering wander or vague feel | Severely worn or seized joint | Late stage, axle may snap |
Park lock to lock and drive a tight figure eight at 5 mph. The clicking will tell you which side.
Boot replacement vs axle replacement
If the boot is torn and you catch it within a few hundred miles, you can sometimes save the joint:
- Pull the axle.
- Clean the joint thoroughly.
- Inspect ball tracks and the cage for pitting or scoring.
- Repack with the correct moly grease.
- Fit a new boot and clamps.
If the joint clicks already, the wear is done. Replace the whole axle.
Cost breakdown
| Item | DIY part | Shop total |
|---|---|---|
| Boot kit | $15 to $40 | $180 to $400 (labor is most of it) |
| Aftermarket axle (one side) | $80 to $250 | $250 to $550 |
| OEM axle | $200 to $600 | $400 to $900 |
| Both front axles done together | $160 to $500 in parts | $500 to $1,100 |
A Honda Civic, Toyota Corolla, or Ford Focus is at the low end. A 2018 Ford F-150 4WD front axle, an Audi Q5, or a BMW X5 sits at the high end. AWD vehicles cost more because there is often a center support bearing or carrier to deal with.
How far you can drive on a clicking CV joint
The clicking phase usually lasts a few hundred to a few thousand miles, depending on how often you turn. Daily commute on highways: a long time. Tight parking lots and city driving: much shorter. When the joint starts to grind or the click becomes a clunk, stop driving it. A CV joint that fails completely on the highway can lock or shear and damage the transmission output shaft, brake hose, or fender.
What accelerates the wear
- Lifted or lowered suspension that runs the joint at a steeper angle than designed.
- Hot-rod launches from a stop, especially on FWD.
- Towing or heavy roof loads on FWD vehicles.
- Off-roading with stock axles in an AWD crossover.
- Skipping the cheap boot replacement when you notice a tear.
DIY level
Replacing a complete axle on most front-drive cars is a 2 to 4 hour job at home with a floor jack, a torque wrench, and a 30 to 36 mm axle nut socket. You will need a new axle nut every time (they are one-time-use on most cars). A pickle fork or ball joint separator helps. AWD axles often need a special puller for the inner splines. If you have never done suspension work, the ball joint and tie rod end disconnects are where the surprises tend to be.