Hummer H3. Manual — part 981

Any gear driven unit, especially an automotive drive axle where the engine torque multiplication
occurs at a 90 degree turn in the driveline, produces a certain amount of noise. Therefore, an
interpretation must be made for each vehicle in order to determine where the noise is normal or if
a problem actually exists. A certain amount of noise must be expected and cannot be eliminated
by conventional repairs or adjustment.

Normal axle noise can be described as a slight noise heard only at a certain speed or under
unusual or remote conditions. For example, the noise tends to reach a peak at speeds from 60-100
km/h (40-60 mph) depending on road and load conditions or on gear ratio and tire size. This
slight noise is in no way indicative of trouble in the axle assembly.

Driveline noises may confuse even the best technician. Vehicle noises coming from tires,
transmission, propeller shaft, universal joints and front or rear wheel bearings are often mistaken
for axle noise.

Visual/Physical Inspection

Inspect the system for loose or missing fasteners.

Inspect the system for leaking components.

Inspect the system for obvious damage or conditions which may cause the symptom.

Symptom List

Refer to a system diagnostic procedure from the following list in order to diagnose the symptom:

Rear Drive Axle Noises

Noisy in Drive

Noisy When Coasting

Intermittent Noise

Constant Noise

Noisy on Turns

REAR DRIVE AXLE NOISES

Gear Noise

Gear noise or whine is audible from 32-89 km/h (20-55 mph) under 4 driving conditions:

Drive- Acceleration or heavy pull

Road Load-Vehicle driving load or constant speed

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

Float-Using enough throttle to keep the vehicle from driving the engine, the vehicle slows
down gradually but the engine still pulls slightly

Coast-Throttle is closed and the vehicle is in gear

Gear noise most frequently has periods where the noise is more prominent, usually between 48-64
km/h (30-40 mph) and 80-85 km/h (50-53 mph). Gear whine is corrected by either ring and
pinion gear replacement or adjustment, depending on the mileage of the gearset.

Bearing Noise

Faulty bearings produce a rough growl or grating sound, rather than the whine typical of gear
noise. Bearing noise/hum will pulsate at a constant vehicle speed. This indicates a bad pinion or a
bad rear axle side bearing. This noise can be confused with rear wheel bearing noise. Inspect and
replace the bearings and the affected components as required.

Rear Wheel Bearing Noise

A rough rear wheel bearing produces a noise which continues with the car coasting at low speed
and the transmission in neutral. The noise may diminish some when the brakes are gently applied.
The noise may also change when performing side-to-side maneuvers with the vehicle.

A rough/noisy rear wheel bearing can be heard by spinning the rear wheels by hand and listening
at the hubs for the noise. Inspect and replace the bearings and the affected components as needed.

Knock at Low Speeds

A low speed knock can be caused by a differential case side gear bore that has worn oversize.
Inspect the side gears and differential case and replace the components as necessary.

Backlash Clunk

Excessive backlash clunk under acceleration or deceleration can be caused by any of the
following:

Worn differential pinion shaft

Worn differential pinion and/or side gear teeth

Worn thrust washers

Excessive clearance between the side gears and the axle shafts

Excessive clearance between differential side gears and the bore in the case

Excessive drive pinon and ring gear backlash

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

Inspect, adjust or replace the affected components as necessary.

NOISY IN DRIVE

Noisy in Drive

NOISY WHEN COASTING

Noisy When Coasting

Cause

Correction

DEFINITION: A noise heard during acceleration load.
Excessive pinion to ring gear
backlash

Adjust the pinion to ring gear backlash. Refer to Backlash
Adjustment.

Worn pinion and ring gear

Replace the pinion and the ring gear. Refer to Drive Pinion
and Ring Gear Replacement.

Worn pinion bearings

Replace the pinion bearings. Refer to Drive Pinion Bearings
Replacement.

Loose pinion bearings

Adjust the pinion bearings preload. Refer to Pinion Depth
Adjustment .

Excessive pinion end play

Adjust the pinion end play. Refer to Pinion Depth
Adjustment .

Worn differential bearings

Replace the differential bearings. Refer to Differential Side
Bearings Replacement.

Loose differential bearings

Adjust the differential bearing preload. Refer to Differential
Side Bearing Preload Adjustment.

Excessive ring gear runout

Replace the ring gear. Refer to Drive Pinion and Ring Gear
Replacement.

Low oil level

Fill the fluid level to specifications with the proper lubricant.
Refer to Rear Axle Lubricant Level Inspection.

Wrong or poor grade oil

Drain and refill the system with the proper lubricant. Refer to
Rear Axle Lubricant Replacement.

Bent axle housing

Replace the axle housing. Refer to Rear Axle Housing
Replacement.

Checks

Action

DEFINITION: Noise is audible when slowing down and disappears when driving.
Worn pinion and ring gear

Adjust or replace the pinion and the ring gear. Refer to Drive
Pinion and Ring Gear Replacement.

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3

INTERMITTENT NOISE

Intermittent Noise

CONSTANT NOISE

Constant Noise

NOISY ON TURNS

Noisy on Turns

WHEEL BEARING WEAR - REAR DRIVE AXLE (STRAIGHT)

Straight Roller Bearing Diagnosis

Pinion and ring gear too
tight

Adjust the pinion and the ring gear backlash. Refer to
Backlash Adjustment.

Checks

Action

Warped ring gear

Replace the ring gear. Refer to Drive Pinion and Ring Gear
Replacement.

Loose differential case bolts Tighten differential case bolts to specifications. Refer to

Fastener Tightening Specifications.

Checks

Action

Flat spot on the pinion or
the ring gear teeth

Replace the pinion and the ring gear. Refer to Drive Pinion
and Ring Gear Replacement.

Flat spot on the pinion
bearing

Replace the bearing. Refer to Drive Pinion Bearings
Replacement.

Worn pinion splines

Replace the pinion. Refer to Drive Pinion and Ring Gear
Replacement.

Worn axle shaft dowel holes Replace the axle shaft. Refer to Rear Axle Shaft

Replacement.

Worn hub studs

Replace the wheel studs. Refer to Wheel Stud Replacement .

Bent axle shaft

Replace the axle shaft. Refer to Rear Axle Shaft
Replacement.

Checks

Action

Worn axle shaft splines

Replace the axle shaft. Refer to Rear Axle Shaft
Replacement.

2007 Hummer H3

2007 Driveline/Axle Rear Drive Axle - H3