Driveline maintenance
See Figures 15 and 16

Maintenance includes inspecting the level of and changing the gear lubricant, and lubricating the universal joints if they are equipped with zerk-type grease fittings. Apply high temperature chassis grease to the U-joints. CV-joints require special grease, which usually comes in a kit along with a new rubber boot.

Most modern universal joints are of the "extended life" design, meaning that they are sealed and require no periodic lubrication. However, it is wise to inspect the joints for hidden grease plugs or fittings, initially.

Also, inspect the driveline for abnormal looseness, whenever the vehicle is serviced.

Figure 15 Some U-joints are equipped with grease (zerk) fittings. Lubricate these using a grease gun.

Figure 16 Recommended driveshaft and differential service locations for rear-wheel drives.

CV boot inspection
See Figures 23 and 24

It is vitally important during any service procedures requiring boot handling, that care be taken not to puncture or tear the boot by over tightening clamps, misuse of tool(s) or pinching the boot. Pinching can occur by rotating the CV joints (especially the tripod) beyond normal working angles.

The driveshaft boots are not compatible with oil, gasoline, or cleaning solvents. Care must be taken that the boots never encounter any of these liquids.

The ONLY acceptable cleaning agent for driveshaft boots is soap and water. After washing, the boot must be thoroughly rinsed and dried before reusing.

Many manufacturers recommend inspecting the CV boots at every oil change (every 3,000 miles or 4,800 km). However, a good rule of thumb is that, if the vehicle needs to be raised for any procedure, check the CV boots. Noticeable amounts of grease on areas adjacent to or on the exterior of the CV joint boot is the first indication that a boot is punctured, torn or that a clamp has loosened. When a CV joint is removed for servicing of the joint, the boot should be properly cleaned and inspected for cracks, tears and scuffed areas on the interior surfaces. If any of these conditions exist, boot replacement is recommended.

Figure 23 Inspect CV boots periodically for damage.

Figure 24 A torn boot should be replaced immediately.

Basic drive axle problems

Drive axle problems frequently give warnings in the form of abnormal noises. Unfortunately, they are often confused with noise produced by other parts.

First, determine when the noise is most noticeable.

• Drive noise: Produced during vehicle acceleration.
• Coast noise: Produced while the vehicle coasts with a closed throttle.
• Float noise: Occurs while maintaining constant vehicle speed on a level road.

Second, make a thorough check to be sure the noises are coming from the drive axle, and not from some other part of the car.

Road noise

Brick or rough concrete roads produce noises that seem to come from the drive axle. Road noise is usually identical whether driving or coasting. Driving on a different type of road will tell whether the road is the problem.

Tire noise

Tire noises are often mistaken for drive axle problems. Snow treads or unevenly worn tires produce vibrations seeming to originate elsewhere. Temporarily inflating the tires to 40 psi will significantly alter tire noise, but will have no effect on drive axle noises (which normally cease below about 30 mph).

Engine or transmission noise

Determine at what speed the noise is most pronounced and then stop the vehicle in a quiet place. With the transmission in Neutral, run the engine through speeds corresponding to road speeds where the noise was noticed. Noises produced with the vehicle standing still are coming from the engine or transmission.

Front wheel bearings

While holding the vehicle speed steady, lightly apply the foot brake; this will often decrease bearing noise, as some of the load is taken from the bearing.

Drive axle noises

Eliminating other possible sources can narrow the cause to the drive axle, which normally produces noise from worn gears or bearings. Gear noises tend to peak in a narrow speed range, while bearing noises will usually vary in pitch with engine speeds.

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