Front Axle - 195FIA

FRONT AXLE - 195FIA

GEAR NOISE

Axle gear noise can be caused by insufficient lubricant, incorrect backlash, tooth contact, worn/damaged gears or the carrier housing not having the proper offset and squareness.

Gear noise usually happens at a specific speed range. The noise can also occur during a specific type of driving condition. These conditions are acceleration, deceleration, coast, or constant load.

When road testing, first warm-up the axle fluid by driving the vehicle at least 5 miles and then accelerate the vehicle to the speed range where the noise is the greatest. Shift out-of-gear and coast through the peak-noise range. If the noise stops or changes greatly check for:

- Insufficient lubricant

Differential side and pinions gears, usually do not cause noise during straight-ahead driving, when the gears are unloaded. The side gears are loaded during turns. A worn pinion mate shaft can also cause a snapping or a knocking noise.

BEARING NOISE

Bearing noise can be either a whining or a growling sound.

Pinion bearings have a constant high pitch noise, because it rotates at a faster rate. This noise changes with vehicle speed.

Differential bearings usually produce a low pitch noise. The differential bearing noise is constant and varies only with vehicle speed.

LOW SPEED KNOCK

Low speed knock is generally caused by:

- Worn U-joints/CV joint
- Worn side-gear thrust washers
- Worn pinion shaft bore

VIBRATION

Vibration at the rear of the vehicle is usually caused by:

- Damaged drive shaft
- Missing drive shaft balance weight(s)
- Worn or out-of-balance wheels
- Loose wheel lug nuts
- Worn U-joints/CV joint
- Loose/broken springs
- Loose pinion gear nut
- Excessive pinion yoke run out

Check for loose or damaged front-end components or engine/transmission mounts. These components can contribute to what appears to be an axle vibration. Also look at engine accessories, brackets and drive belts.

NOTE: All driveline components should be examined before starting any repair.

DRIVELINE SNAP

A snap or clunk noise when the vehicle is shifted into gear or the clutch engaged, can be caused by:

- High engine idle speed
- Transmission shift operation
- Loose engine/transmission/transfer case mounts
- Worn U-joints/CV joint
- Loose spring mounts
- Loose pinion gear nut and yoke
- Excessive ring gear backlash
- Excessive side gear to case clearance

To determined the source of a snap/clunk noise, raise vehicle on a hoist with the wheels free to rotate. Have a helper shift the transmission into gear and listen for the noise.

DIAGNOSTIC CHART