Front wheel drive vehicles have what is known as a half-shaft that delivers the power from the engine to the transaxle and then on to the wheels. These half-shaft axles are called constant velocity axles - more commonly known as CV axles. While they are most commonly found in front wheel drive vehicles, some all-wheel drive and four wheel drive cars and trucks also use these axles.
CV axles consist of an inner and an outer CV joint that deliver the power at constant speeds over a variety of road conditions. They work with the suspension.
The joints have little rubber boots on them that hold in packed grease to lubricate the joints. The boots keep dirt and other debris out of the grease. Boots are made to last quite a while, but they are rubber, and they can dry out and crack. An improperly lubricated joint will fail.
If you have CV joints on your Saturn, you should make it a point to inspect them regularly for wear or damage. The inner joint gets less abuse than the outer, so it is the outer that usually fails. A boot is usually responsible for a joint going bad because it has opened up the joint to elements that can damage it. However, the joint itself can wear out, and when it wears, it becomes looser, and that makes more room for parts to bang together and break.
When a CV joint is bad, you will hear it making noises. There will be clicking, grinding and popping noises. Turn your Saturn in a tight circle and listen for noise. A bad joint can also make a consistent knock at a low speed, or it can cause the steering wheel to vibrate at certain speeds.
You can inspect the boot and the joint for wear or damage by doing a visual inspection of the boots.
Inspect the Boot
- Park your vehicle on a flat, dry surface and set the emergency brake. You may need to put it on jack stands to inspect it.
- Take your flashlight and get under the vehicle. You need to be able to see the axle.
- Check the boots for damage like cracks or tears. You may even be missing a boot clamp. Feel each one for grease. There should not be any grease on the outside of the boot. If you feel grease, you have a damaged boot that is leaking.
- The absence of grease or tears means the boot is in good shape.
Inspect the Axle
- Use the above steps as a starting point and then visually inspect the axle for damage.
- Grab hold of the axle and try to move it sideways and in and out. You should have very little movement of the axle, so if you can move it any more than an eighth of an inch in any direction, you probably need to replace it.
- Take it down off the jacks and drive it in a tight circle and listen for the telltale noises of a bad CV joint.
Once you have determined the cause of the problem, replace the bad parts. If you have trouble and need assistance, then take your vehicle to your nearest GM dealership.