What a CV Shaft Does and When It Needs Replacing

A CV shaft (constant velocity shaft) connects your transmission to your front wheels and lets power flow to them while the wheels turn and bounce. On front-wheel-drive cars, you have two—one on each side. When a CV shaft fails, your car won't move forward, or you'll hear a loud clicking noise when you turn, feel vibration at highway speed, or see grease splattered inside your wheel.

You can replace a CV shaft yourself if you have basic tools and mechanical confidence. The job takes two to four hours per side, depending on your car's design. If you're not comfortable working under a car or don't have a jack and jack stands, a shop will charge between $300 and $800 per shaft, including labor and parts.

Key Takeaways

  • You will need a jack, jack stands, a socket set, a pry bar, and a rubber mallet to remove the old shaft and install the new one safely.
  • The hardest step is breaking the axle nut loose—it is torqued very tight, so use a breaker bar and find the wheel before you try.
  • The CV shaft slides out of the transmission on one end and out of the wheel hub on the other, but the transmission end often requires a pry bar to separate.
  • New CV shafts come pre-packed with grease and ready to install; you do not need to disassemble or repack them yourself.
  • After installation, torque the axle nut to your car's specification (usually 150 to 200 foot-pounds) and test-drive before returning to normal use.

Gather Your Tools and Parts Before You Start

You will need a floor jack and at least two jack stands rated for your car's weight. Never work under a car supported only by a jack. You also need a socket set (metric or standard, depending on your car), a breaker bar, a rubber mallet, a pry bar, and wheel chocks to block the wheels that stay on the ground.

Buy a replacement CV shaft from a parts store or online retailer. Most new shafts cost $80 to $250 each and come ready to install. Write down your car's year, make, model, and engine size before you order—the shaft must match your transmission type (automatic or manual) and your car's wheelbase.

You may also need a CV axle puller (a specialized tool that costs $20 to $50) if the shaft is stuck in the wheel hub. Many parts stores loan tools for free or a small deposit if you buy parts from them. Ask before you start.

Remove the Wheel and Break the Axle Nut Loose

Park on level ground, engage the parking brake, and place wheel chocks behind the rear wheels. Loosen the lug nuts on the wheel you are working on while the car is still on the ground—do not remove them yet. Then raise the car with the floor jack and find it with jack stands under the frame, not the suspension.

Remove the lug nuts and the wheel. You will now see the axle nut at the center of the wheel hub. This nut is torqued very tight (usually 150 to 200 foot-pounds) and will not budge with a regular wrench. Use a breaker bar (a long handle that multiplies your leverage) and a socket that fits the nut snugly. If the wheel spins while you turn the breaker bar, have someone press the brake pedal hard, or wedge the wheel with a block of wood.

Once the nut breaks loose, you can remove it by hand. Set it aside in a safe place—you will reuse it.

Disconnect the CV Shaft from the Wheel Hub

The CV shaft is held in the wheel hub by a spline (a series of ridges that lock together). To separate them, you need to pull the hub away from the shaft. Use a CV axle puller if you have one: thread it onto the shaft and turn the center bolt to pull the hub off. If you do not have a puller, a pry bar and rubber mallet work on many cars—wedge the pry bar between the hub and the suspension and tap the mallet gently until the shaft slides out.

Do not hit the shaft itself or the threads at the end. If the shaft is very stuck, spray penetrating oil around the hub and wait 15 minutes before trying again. Once the shaft is free, hang the wheel hub with a wire or bungee cord so it does not hang by the brake hose.

Remove the CV Shaft from the Transmission

The other end of the CV shaft is inserted into the transmission. On many cars, you can straightforward pull it straight out. On others, especially front-wheel-drive cars with the engine mounted sideways, the shaft is held by a clip inside the transmission and will not budge without help.

Try pulling the shaft straight out first. If it does not move, use a pry bar to gently separate the inner CV joint from the transmission housing. Work slowly and do not force it—you are breaking a seal, not breaking the shaft. Once the seal breaks, the shaft should slide out. If transmission fluid leaks out, place a drain pan underneath and be ready to refill it later.

Install the New CV Shaft

Before you insert the new shaft, wipe the spline (the ridged end that goes into the transmission) with a clean cloth. Slide the transmission end into the housing first. You will feel it click or seat when it is fully inserted. Push firmly until you are sure it is all the way in.

Next, align the wheel-hub end of the shaft with the spline inside the hub and push it in until it seats. The shaft should not wobble or feel loose. If it does, pull it out and check that both splines are clean and aligned.

Once the shaft is seated, reinstall the axle nut by hand and tighten it snugly with a socket and breaker bar. Do not torque it to full specification yet—you will do that after the wheel is back on and the car is on the ground.

Reinstall the Wheel and Torque the Axle Nut

Remove the wire or bungee cord holding the wheel hub. Align the wheel with the lug holes and slide it onto the hub. Thread the lug nuts by hand and tighten them snugly with a socket wrench, but do not fully tighten them yet.

Lower the car to the ground with the floor jack. Once the car is resting on all four wheels, use a torque wrench to tighten the lug nuts in a star pattern (opposite sides, then the remaining two) to your car's specification—usually 80 to 100 foot-pounds. Then torque the axle nut to the specification in your owner's manual, typically 150 to 200 foot-pounds.

If you do not have a torque wrench, tighten the axle nut as tight as you can with a breaker bar, then have a shop verify the torque with a wrench. An undertorqued nut can loosen and cause the shaft to fall out; an overtorqued nut can strip the threads.

Test Drive and Check for Leaks

Before you return to normal driving, take a short test drive at low speed. Listen for clicking noises when you turn the steering wheel—a new CV shaft should be silent. Feel for vibration at highway speed. If you hear clicking or feel vibration, stop and check that the axle nut is tight and the shaft is fully seated in the hub.

Check under the car for transmission fluid leaks where the shaft enters the transmission. A small amount of seepage is normal for the first few miles, but steady dripping means the seal did not seat properly. If that happens, the shaft may need to be removed and reseated, or the transmission seal may need replacement.

Frequently Asked Questions

Can I replace just one CV shaft or do I have to replace both?

You can replace one shaft at a time. However, if both shafts are the same age and mileage, the second one may fail soon after. Some shops recommend replacing both together to avoid a second job in a few months, but it is not required.

What if the axle nut won't come loose?

Spray penetrating oil around the nut and let it soak for 30 minutes. Use a longer breaker bar for more leverage, or have someone press the brake pedal while you turn. If it still will not budge, a shop can remove it with an impact wrench, which is faster and safer than forcing it by hand.

How do I know if I need a CV axle puller?

Try removing the shaft without one first. If the hub will not separate from the shaft after you have pulled hard, then you need a puller. Most auto parts stores loan them for free with a parts purchase, so ask before you buy one.

Do I need to refill transmission fluid after replacing the shaft?

Check the transmission fluid level after the job is done. If it is low, add the type specified in your owner's manual. Most cars lose only a small amount when the shaft is removed, but it is worth checking to be sure.

What should the new CV shaft cost?

Prices vary by car model and brand. Aftermarket shafts typically cost $80 to $250 each. OEM (original equipment manufacturer) shafts cost more, usually $150 to $400. Rebuilt shafts are cheaper but less reliable. Buy from a reputable parts store and ask about the warranty.