SMU - Propeller Shaft and Rear Drive Axle Diagnostic Information
| Subject: | Propeller Shaft and Rear Drive Axle Diagnostic Information |
| Models: | 2001 Chevrolet Camaro |
| 2001 Pontiac Firebird |
This bulletin is being issued to add diagnostic information in the Propeller Shaft sub-section and the Rear Drive Axle sub-section of the Service Manual.
The following information has been added to SI2000. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected pages.
Propeller Shaft
Diagnostic Starting Point - Propeller Shaft
Begin the propeller shaft system diagnosis with the Diagnostic Starting Point - Vibration Diagnosis in Vibration Diagnosis and Correction. The use of the Diagnostic Starting Point will determine if the concern is related to the propeller shaft. When instructed to exit the Vibration Diagnosis and Correction diagnostic and return to the Diagnostic Starting Point - Propeller Shaft, proceed to Symptoms - Propeller Shaft in order to isolate and identify propeller shaft related concerns.
Symptoms - Propeller Shaft
Review the propeller shaft system function. Refer to Propeller Shaft Description and Operation.
Classifying the Symptom
Propeller shaft symptoms can usually be classified into the following categories:
| • | Leaks |
| • | Noises |
| • | Vibrations |
Leak and noise related symptoms are diagnosed within the propeller shaft section. For vibration related symptoms, refer to Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction.
Visual/Physical Inspection
| • | Inspect the system for aftermarket devices which could affect the operation of the propeller shaft. |
| • | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom. |
Symptom List
In order to diagnose the symptom, refer to the appropriate diagnostic procedure:
| • | Leak at Front Slip Yoke |
| • | Universal Joint Noise |
| • | Ping, Snap, or Click Noise |
| • | Knock or Clunk Noise |
| • | Scraping Noise |
| • | Squeak Noise |
| • | Shudder on Acceleration at Low Speed |
Checks | Action | ||||||
|---|---|---|---|---|---|---|---|
DEFINITION: Evidence of fluid loss at or near the drive pinion yoke and/or on surrounding components. | |||||||
The slip yoke barrel has burrs, or is nicked, corroded, or worn. |
Minor burrs can be removed by careful use of crocus cloth or fine stone honing.
| ||||||
The transmission rear oil seal is worn or damaged. | Replace the oil seal. Refer to the following:
| ||||||
Problem | Action |
|---|---|
One or more of the universal joints are worn or damaged. | Replace the universal joint. Refer to Universal Joint and Slip Yoke Replacement. |
One or more of the universal joints have lost lubricant | Replace the universal joint. Refer to Universal Joint and Slip Yoke Replacement. |
The propeller shaft retaining strap bolts are loose | Tighten the yoke retainer strap bolts to specifications. Refer to Propeller Shaft Replacement - One Piece or Propeller Shaft Replacement - Two Piece. |
Checks | Action |
|---|---|
DEFINITION: A ping, snap or click that is heard as the transmission is placed in gear or the suspension is loaded. | |
The pinion yoke is loose. | Tighten the bolts and the pinion nut to the specified torque. Refer to Drive Pinion Flange/Yoke and/or Oil Seal Replacement in Rear Drive Axle. |
One or more of the universal joints are worn or damaged. | Replace the universal joint. Refer to the following Universal Joint and Slip Yoke Replacement. |
Checks | Action |
|---|---|
DEFINITION: Knocking or clunking noise occurs when operating the vehicle at a steady speed in high gear or coasting in neutral at 16 km/h (10 mph). | |
One or more of the universal joints are worn or damaged. | Replace the universal joint. Refer to the following Universal Joint and Slip Yoke Replacement. |
The side gear hub counterbore in the differential is worn oversize. | Replace the differential case and/or the side gears. Refer to Differential Carrier Assembly Replacement in Rear Drive Axle. |
Checks | Action |
|---|---|
DEFINITION: A constant scraping noise occurs when operating the vehicle, regardless of road speed. | |
Loose or damaged components contacting a rotating assembly or component. | Visually inspect the vehicle underbody and correct the interference as necessary. |
Checks | Action |
|---|---|
DEFINITION: When driving the vehicle at various speeds, a rhythmic squeak occurs increasing in frequency as vehicle speed increases. | |
Loss of lubricant in one or more of the universal joint bearing caps. | Replace the universal joint. Refer to Universal Joint and Slip Yoke Replacement. |
Rear Drive Axle
Diagnostic Starting Point - Rear Drive Axle
Begin the rear drive axle system diagnosis with the Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction. The use of the Diagnostic Starting Point - Vibration Diagnosis and Correction will determine if the concern is related to the rear drive axle. When instructed to exit the Vibration Diagnosis and Correction diagnostic and return to the Diagnostic Starting Point - Rear Drive Axle, proceed to Symptoms - Rear Drive Axle in order to isolate and identify rear drive axle related concerns.
Symptoms - Rear Drive Axle
Review the rear drive axle system function. Refer to Rear Axle Description.
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
In order to diagnose the noise symptom, refer to the appropriate diagnostic procedure:
| • | Noise Diagnosis - Rear Drive Axle |
| • | Noisy in Drive |
| • | Noisy When Coasting |
| • | Intermittent Noise |
| • | Constant Noise |
| • | Noisy on Turns |
Noise Diagnosis - Rear Drive Axle
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 |
| • | 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
Worn or damaged bearings produce a rough growl or grating sound, rather than the whine typical of gear noise. Bearing noise or hum will pulsate at a constant vehicle speed. This indicates worn or damaged pinion bearings or rear axle side bearings. 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 worn or damaged rear wheel bearing produces a noise which continues with the car coasting at low speed and the transmission in neutral. The noise may diminish slightly as the brakes are gently applied. The noise may also change when performing side-to-side maneuvers with the vehicle.
A worn or damaged 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 gear teeth. |
| • | Worn differential 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. |
Inspect, adjust or replace the affected components as necessary.
Checks | Action |
|---|---|
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 Differential Carrier Assembly - Disassemble. |
Worn pinion bearings | Replace the pinion bearings. Refer to Pinion Depth Adjustment. |
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 Carrier Assembly - Disassemble. |
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 Differential Carrier Assembly - Disassemble. |
Low oil level | Fill the fluid level to specifications with the proper lubricant. Refer to Lubricant Level Check. |
Wrong or poor grade oil | Drain and refill the system with the proper lubricant. Refer to Rear Axle Housing Cover and Gasket Replacement. |
Bent axle housing | Replace the axle housing. Refer to Rear Axle Replacement. |
Checks | Action |
|---|---|
Worn pinion and ring gear | Adjust or replace the pinion and the ring gear. Refer to Differential Carrier Assembly - Disassemble. |
Insufficient pinion and ring gear backlash | Adjust the pinion and the ring gear backlash. Refer to Backlash Adjustment. |
Checks | Action |
|---|---|
Warped ring gear | Replace the ring gear. Refer to Differential Carrier Assembly - Disassemble. |
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 Differential Carrier Assembly - Disassemble. |
Flat spot on the pinion bearing | Replace the bearing. Refer to Drive Pinion Disassemble. |
Worn pinion splines | Replace the pinion. Refer to Differential Carrier Assembly - Disassemble. |
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 in Rear Suspension. |
Bent axle shaft | Replace the axle shaft. Refer to Rear Axle Shaft Replacement. |
Checks | Action |
|---|---|
Worn differential pinion gears | Replace the pinion gears. Refer to Differential Carrier Assembly - Disassemble. |
Worn axle shaft splines | Replace the axle shaft. Refer to Rear Axle Shaft Replacement. |
