WHAT ARE CV AXLES?
CV axle joints stand for “constant velocity” axle joints. These types of axle joints are used primarily in front wheel drive cars. However, they’re being seen more often lately as rear drive axles as well.
The CV axles are needed to transfer the power from the transmission to the wheels. These axles must accommodate up and down motions of the suspension and allow the wheels to turn side to side.
The first thing our technicians check when inspecting suspension on a FWD vehicle are the CV joint boots. The ideal time to replace the CV joint boot is when they show signs of cracking or weathering but have not yet split. If your CV boot(s) has split, there’s a good chance of having to replace the entire axle shaft assembly.
CV boots usually split between 80,000 and 120,000kms. Our trained technicians at Dale’s will inspect your vehicle’s axles and inform you of any repairs that they may need.
When a boot has failed, there is always some uncertainly about the condition of the CV joint and whether or not it has become contaminated with dirt and/or suffered wear or damage. If the joint is making noise, the joint is obviously damaged and needs to be replaced. Sudden failures of constant velocity joints are rare, but CV joints do wear out and may fail because of age.
Newer rear wheel drive and AWD cars with independent rear suspension also have a similar setup. However instead of the cv axle shafts going from side to side out of the transmission, a drive shaft from the rear of the transmission travels the length of the car and mounts to a differential.
A “clunk” when accelerating, decelerating or when putting the transaxle into drive This kind of noise can come from excessive play in the inner joint on FWD passenger cars and various 4X4 light truck applications.
A shudder or vibration when accelerating Excessive play in either the inboard or outboard joints can sometimes cause this, but the most likely cause is a worn inboard plunge joint.
First of all, what are universal joints? Here is a blown up picture of a universal joint:
Universal joints or “u-joints” are flexible mechanical connectors used to transmit rotary motion from one shaft to another shaft that is not in line with the first, or when alignment varies during service.
Axle u-joints are found on the driveshafts of rear wheel drive & 4-wheel drive vehicles. Worn or seized u-joints can cause shuddering or squeaking while accelerating or binding in the steering while cornering in 4X4’s. It is important to have u-joints replaced as soon as these symptoms arise as damage to other components is certain.
A U-joint that is failing usually produces various symptoms:
- Shudder as car accelerates from stop or low speed
- Loud clunk in driveshaft when shifting gears
- Rotational squeaking noise at low speeds
- Roughness or vibration at any speed