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Front Drive Axle: Diagnosis Chevrolet Silverado 1500

Differentials & Drive Axles 21 illustrations ~3075 words

Noise Diagnosis

Any gear-driven unit produces a certain amount of noise that is normal and that conventional repairs or adjustment cannot eliminate. Slight noise that is heard only at a certain speed or under unusual or remote conditions is acceptable. For example, this noise tends to reach a peak at speeds from 60-100 km/h (40-60 mph) depending upon road and load conditions, or upon gear ratio and tire size. Noise of this kind does not indicate trouble in the axle assembly.

When an axle is suspected of being noisy, make a thorough test in order to determine whether the noise originates in the tires, road surface, wheel bearings, engine, transmission, propeller shaft, or axle assembly.

Classifying the Symptom

Front Drive Axle symptoms can usually be classified into the following categories

  1. Leaks
  2. Noises
  3. Vibrations

Leak and noise related symptoms are diagnosed within the Front Drive Axle section. For vibration related symptoms, refer to Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction.

Visual/Physical Inspection

  1. Inspect the system for loose or missing fasteners.
  2. Inspect the system for loose or leaking components.
  3. Inspect the system for obvious damage or conditions which may cause the symptom.

Symptoms List

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

  1. «Front Drive Axle Noises»(ref-238218-S29379645022006072400000)
  2. «Noisy in Drive»(ref-238218-S30394613352006072400000)
  3. «Noisy When Coasting»(ref-238218-S29561500482006072400000)
  4. «Intermittent Noise»(ref-238218-S32013764152006072400000)
  5. «Constant Noise»(ref-238218-S36796187842006072400000)
  6. «Noisy on Turns»(ref-238218-S01935187952006072400000)
  7. «Front Axle Lubricant Leak Diagnosis»(ref-238218-S35970499242006072400000)

Straight Roller Bearing Diagnosis

Consider the following factors when diagnosing a bearing condition

  1. Note the general condition of all parts during disassembly and inspection.
  2. Classify the failure with the aid of the illustrations.
  3. Determine the cause.
  4. Make all repairs following recommended procedures.

Tapered Roller Bearing Diagnosis

Consider the following factors when diagnosing bearing condition

  1. General condition of all parts during disassembly and inspection.
  2. Classify the failure with the aid of the illustrations.
  3. Determine the cause.
  4. Make all repairs following recommended procedures.

Front Axle Lubricant Leak Diagnosis

Front axle lubricant leaks can occur at the following locations

  1. Axle shaft oil seals
  2. Differential carrier assembly mating surface
  3. Drain plug
  4. Fill plug
  5. Inner axle tube assembly to differential carrier assembly mating surface
  6. Pinion yoke oil seal
  7. Vent tube

Inspection Procedure

Perform the following before disassembling the axle

  1. Remove the fill plug from the axle.
  2. Remove the drain plug from the axle.
  3. Drain the axle lubricant.
  4. Inspect the oil and the case for metal chips. Determine the source of the metal chips, such as a broken gear or bearing cage.
  5. Check the ring gear backlash. Refer to «Backlash Inspection and Adjustment»(ref-238218-S16334764172006072400000) .

This information can be used in order to determine the cause of the axle problem. The information will also help when setting up and preloading the differential case.

Determine the cause of the axle problem before disassembly, if possible.

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  1. Remove the upper differential carrier assembly bushing by performing the following steps: Install the J 36616-2 (1), the J 33791-1 (2), the thrust bearing (3), the J 21474-18 (4), and the forcing screw as shown. Remove the upper differential carrier assembly bushing by holding the forcing screw and tightening the J 21474-18.
  2. Remove the lower differential carrier assembly bushing by performing the following steps: Install the J 21474-18 (1), the thrust bearing (2), the J 33791-1 (3), the J 36616-2 (4), and the forcing screw as shown. Remove the lower differential carrier assembly bushing by holding the forcing screw and tightening the J 21474-18.
  3. Remove the front axle actuator.
  4. Remove the inner axle shaft housing to differential carrier assembly bolts.
  5. Carefully remove the inner axle shaft housing with the inner axle shaft and clutch fork components from the differential carrier assembly.
  6. Remove the following components from the inner axle shaft housing (4): The clutch fork inner spring (10) The clutch fork assembly (11) The clutch shaft shim (9) The clutch shaft sleeve (8) The retainer ring (7) The thrust washers (5, 6)
  7. Remove the inner axle shaft (2).
  8. Remove the inner axle shaft bearing and the inner axle shaft seal by performing the following steps: Install the inner axle shaft housing into a vise. Clamp only on the mounting flange of the inner axle shaft housing. Install the J 29369-2 (1) behind the inner axle shaft bearing. See «Special Tools»(ref-238218-S10438743342006072400000) .
  9. Install the J 2619-01 (2) to the J 29369-2 (1). See «Special Tools»(ref-238218-S10438743342006072400000) .
  10. Remove the inner axle shaft bearing and the inner axle shaft bearing and the seal using the J 2619-01 .
  11. Remove the inner axle shaft housing from the vise.
  12. Remove the front drive axle clutch shaft.
  13. Use the J 34011 in order to remove the clutch shaft bearing. See «Special Tools»(ref-238218-S10438743342006072400000) .
  14. Place the differential carrier assembly into a vise. Clamp only on the mounting flange of the differential carrier assembly case.
  15. Remove the inner axle shaft using a hammer and a brass drift.
  16. Install the J 29369-2 (1) behind the inner axle shaft bearing. See «Special Tools»(ref-238218-S10438743342006072400000) .
  17. Install the J 2619-01 (2) to the J 29369-2 (1). See «Special Tools»(ref-238218-S10438743342006072400000) .
  18. Remove the inner axle shaft bearing and the inner axle seal bearing and the seal using the J 2619-01 .
  19. Remove the differential carrier assembly from the vise.
  20. Remove the vent connector.
  21. Remove the differential carrier assembly bolts.
  22. Separate the left carrier case half from the right carrier case half by tapping on the on the carrier case with a hammer and a brass drift.
  23. Remove the differential case assembly. Disconnect the right side differential bearing adjuster nut lock from the differential bearing adjuster nut by prying up on the lock.
  24. Remove the left side differential bearing adjuster nut lock and the bolt.
  25. Remove the left side differential bearing adjuster by doing the following: Install the J 36615 onto the differential bearing adjuster nut as shown. See «Special Tools»(ref-238218-S10438743342006072400000) . Turn the J 36615 counterclockwise in order to remove the differential bearing adjuster nut and the O-ring. See «Special Tools»(ref-238218-S10438743342006072400000) .
  26. Remove the right side differential bearing adjuster by doing the following: Install the J 36599-A onto the differential bearing adjuster nut. See «Special Tools»(ref-238218-S10438743342006072400000) . Turn the J 36599-A clockwise in order to push the bearing cup out of the bore. See «Special Tools»(ref-238218-S10438743342006072400000) .
  27. Remove the right side differential bearing adjuster nut sleeve using a hammer and brass drift.
  28. Install the J 8614-01 as shown. See «Special Tools»(ref-238218-S10438743342006072400000) . Remove the pinion nut while holding the J 8614-01 . See «Special Tools»(ref-238218-S10438743342006072400000) .
  29. Remove the washer.
  30. Install the J 8614-2 (2) and the J 8614-3 (3) into the J 8614-01 (1) as shown. See «Special Tools»(ref-238218-S10438743342006072400000) .
  31. Remove the pinion yoke by turning the J 8614-3 (3) clockwise while holding the J 8614-01 (1). See «Special Tools»(ref-238218-S10438743342006072400000) .
  32. Install the J 45765 to the left side differential carrier case half over the drive pinion as shown. See «Special Tools»(ref-238218-S10438743342006072400000) .
  33. Turn the forcing screw of the J 45765 clockwise to remove the following components from the left side differential carrier case half. See «Special Tools»(ref-238218-S10438743342006072400000) . The drive pinion gear The pinion gear selectable shim The inner pinion bearing The collapsible spacer
  34. Remove the drive pinion seal using a suitable seal remover.
  35. Remove the outer pinion bearing from the differential carrier case half.
  36. Install the J 45754-3 over the inner pinion bearing cup.
  37. Install the forcing screw (1) of the J 45754 into the J 45754-3 (2).
  38. Drive out the inner pinion bearing cup by pounding on the forcing screw with a hammer.
  39. Install the J 45754-2 (2) and the forcing screw (1) over the outer pinion bearing cup bore.
  40. Install the J 45754-4 (3) into the pinion bearing bore behind the outer pinion bearing cup. Slowly turn the forcing screw (1) until the J 45754-4 is evenly seated behind the outer pinion bearing cup bore and the J 45754-2 (2) is evenly seated over the outer pinion bearing cup bore.
  41. Remove the outer pinion bearing cup by turning the forcing screw clockwise.
  42. Install the J 22912-01 between the pinion bearing and the drive pinion. See «Special Tools»(ref-238218-S10438743342006072400000) .
  43. Remove the inner pinion bearing using the J 22912-01 and a hydraulic press. See «Special Tools»(ref-238218-S10438743342006072400000) .
  44. Remove the pinion gear selectable shim.

Perform the following before disassembling the axle

  1. Remove the drain plug from the axle.
  2. Drain the axle lubricant.
  3. Inspect the oil and the case for metal chips. Determine the source of the metal chips, such as a broken gear or bearing cage.
  4. Check the ring gear backlash. Refer to «Backlash Inspection and Adjustment»(ref-238218-S16334764172006072400000) .

This information can be used in order to determine the cause of the axle problem. The information will also help when setting up and preloading the differential case.

Determine the cause of the axle problem before disassembly, if possible.

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  1. Remove the upper differential carrier assembly bushing by performing the following steps: Install the J 36616-2 (1), the J 33791-1 (2), the thrust bearing (3), the J 21474-18 (4), and the forcing screw as shown. Remove the upper differential carrier assembly bushing by holding the forcing screw and tightening the J 21474-18.
  2. Remove the lower differential carrier assembly bushing by performing the following steps: Install the J 21474-18 (1), the thrust bearing (2), the J 33791-1 (3), the J 36616-2 (4), and the forcing screw as shown. Remove the lower differential carrier assembly bushing by holding the forcing screw and tightening the J 21474-18.
  3. Remove the front axle actuator, S4WD axle only.
  4. Disconnect the right side inner axle shaft from the differential side gear using a hammer and a brass drift, F4WD axle only.
  5. Remove the inner axle shaft, F4WD axle only.
  6. Remove the inner axle shaft housing to differential carrier assembly bolts.
  7. Remove the inner axle shaft housing, F4WD axle only.
  8. Carefully remove the inner axle shaft housing with the inner axle shaft and clutch fork components from the differential carrier assembly, S4WD axle only.
  9. Remove the following components from the inner axle shaft housing, S4WD axle only: The clutch fork inner spring (10) The clutch fork assembly (11) The clutch shaft shim (9) The clutch shaft sleeve (8) The front drive axle clutch gear (6) by doing the following: Clamp the inner axle shaft housing (4) in a vise. Clamp only on the mounting flange. Strike the inside surface of the shaft (1) flange with a hammer and a brass drift in order to dislodge the front drive axle clutch gear (6) from the inner axle shaft (1). Remove the front drive axle clutch gear (6) Remove the thrust washer (5) Remove the inner axle shaft (1)
  10. Remove the inner axle shaft bearing and the inner axle shaft seal by performing the following steps: Install the inner axle shaft housing into a vise. Clamp only on the mounting flange of the inner axle shaft housing. Install the J 29369-1 (1) behind the inner axle shaft bearing. See «Special Tools»(ref-238218-S10438743342006072400000) . Install the J 2619-01 (2) to the J 29369-1 (1). See «Special Tools»(ref-238218-S10438743342006072400000) . Remove the inner axle shaft bearing and the seal using the J 2619-01 .
  11. Remove the inner axle shaft bearing and the inner axle shaft seal by performing the following steps: Place the differential carrier assembly into a vise. Clamp only on the mounting flange of the differential carrier assembly case. Install the J 29369-1 (1) behind the inner axle shaft bearing. See «Special Tools»(ref-238218-S10438743342006072400000) . Install the J 2619-01 (2) to the J 29369-1 . See «Special Tools»(ref-238218-S10438743342006072400000) . Remove the inner axle shaft bearing and the inner axle shaft seal using the J 2619-01 .
  12. Remove the differential carrier assembly from the vise.
  13. Remove the front drive axle clutch shaft, S4WD axle only.
  14. Use the J 34011 in order to remove the clutch shaft bearing, S4WD axle only. See «Special Tools»(ref-238218-S10438743342006072400000) .
  15. Remove the vent connector.
  16. Remove the differential carrier assembly bolts.
  17. Separate the left carrier case half from the right carrier case half by tapping on the on the carrier case with a hammer and a brass drift.
  18. Remove the differential case assembly. Disconnect the differential bearing adjuster nut locks from the differential bearing adjuster nut by prying up on the locks, S4WD axle - both sides, F4WD axle - left side.
  19. Remove the differential bearing adjuster nuts and the differential bearing cups by doing the following, S4WD axle - both sides, F4WD axle - left side: Install the J 36599-A onto the differential bearing adjuster nut. See «Special Tools»(ref-238218-S10438743342006072400000) . Turn the J 36599-A clockwise in order to push the differential bearing adjuster nut and the bearing cup out of the bore. See «Special Tools»(ref-238218-S10438743342006072400000) .
  20. Remove the differential bearing adjuster nut sleeves using a hammer and brass drift, S4WD axle - both sides, F4WD axle - left side.
  21. Install the J 8614-01 as shown. See «Special Tools»(ref-238218-S10438743342006072400000) . Remove the pinion nut while holding the J 8614-01 . See «Special Tools»(ref-238218-S10438743342006072400000) .
  22. Remove the washer.
  23. Install the J 8614-2 (2) and the J 8614-3 (3) into the J 8614-01 (1) as shown. See «Special Tools»(ref-238218-S10438743342006072400000) .
  24. Remove the pinion yoke by turning the J 8614-3 (3) clockwise while holding the J 8614-01 (1). See «Special Tools»(ref-238218-S10438743342006072400000) .
  25. The steps below explain how to remove the drive pinion and pinion bearing cups using the J 36598 or the J 45765 and the J-45858 . See «Special Tools»(ref-238218-S10438743342006072400000) . Follow the appropriate steps depending on what tool is available.
  26. Install the J 36598 into a vise. See «Special Tools»(ref-238218-S10438743342006072400000) .
  27. Install the left differential carrier case half onto the J 36598 and the J 36598-6. See «Special Tools»(ref-238218-S10438743342006072400000) .
  28. While holding the forcing screw of the J 36598 , turn the handle of the J 36598 counterclockwise in order to remove the pinion with the following components. See «Special Tools»(ref-238218-S10438743342006072400000) . The pinion gear selectable shim The inner pinion bearing The collapsible spacer
  29. Install the J 36598-5 (3) behind the inner pinion bearing cup.
  30. Thread the forcing screw of the J 36598 (1) onto the J 36598-5 (3) until fully seated. See «Special Tools»(ref-238218-S10438743342006072400000) .
  31. While holding the forcing screw of the J 36598 (1), turn the handle of the J 36598 (2) counterclockwise and press the inner bearing cup out from the differential carrier case. See «Special Tools»(ref-238218-S10438743342006072400000) .
  32. Install the J 36598-5 (2) behind the outer pinion bearing cup.
  33. Install the forcing screw of the J 36598 (1) to the J 36598-5 (2). See «Special Tools»(ref-238218-S10438743342006072400000) .
  34. While holding the forcing screw of the J 36598 , turn the handle of the J 36598 clockwise in order to remove the following components. See «Special Tools»(ref-238218-S10438743342006072400000) . The pinion oil seal The pinion outer bearing The pinion outer bearing cup
  35. Install the J 45765 to the left side differential carrier case half over the drive pinion as shown. See «Special Tools»(ref-238218-S10438743342006072400000) .
  36. Turn the forcing screw of the J 45765 clockwise to remove the following components from the left side differential carrier case half. See «Special Tools»(ref-238218-S10438743342006072400000) . The drive pinion gear The pinion gear selectable shim The inner pinion bearing The collapsible spacer
  37. Remove the drive pinion seal using a suitable seal remover.
  38. Remove the outer pinion bearing from the differential carrier case half.
  39. Install the J 45858-4 over the inner pinion bearing cup.
  40. Install the forcing screw (1) of the J 45858 into the J 45858-4 (2).
  41. Drive out the inner pinion bearing cup by pounding on the forcing screw with a hammer.
  42. Install the J 45858-3 (3), the thrust bearing and the washer (2), and the forcing screw (1) over the outer pinion bearing cup bore.
  43. Install the J 45858-5 into the pinion bearing bore behind the outer pinion bearing cup. Slowly turn the forcing screw clockwise until the J 45858-5 is evenly seated behind the outer pinion bearing cup bore and the J 45858-3 is evenly seated over the outer pinion bearing cup bore.
  44. Remove the outer pinion bearing cup by turning the forcing screw clockwise.
  45. Remove the collapsible spacer from the drive pinion.
  46. Install the J 22912-01 between the pinion bearing and the drive pinion. See «Special Tools»(ref-238218-S10438743342006072400000) .
  47. Remove the inner pinion bearing using the J 22912-01 and a hydraulic press. See «Special Tools»(ref-238218-S10438743342006072400000) .
  48. Remove the pinion gear selectable shim.

Differential Case Bearings Inspection

  1. Inspect the bearings for smooth rotation after oiling.
  2. Inspect the bearing rollers for wear.
  3. Inspect the bearing cups for the following conditions: Wear Cracks Brinelling Scoring

Differential Case and Gears Inspection

  1. Inspect the following components for excessive wear and/or fit: The pinion gear shaft The thrust washers The differential case for wear, cracks and scoring The fit of the pinion gear shaft in the differential case The fit of the differential side gears in the differential case The fit of the side gears on the axle shafts
  2. Inspect the teeth of the pinion gears and the differential side gears for the following conditions: Wear Cracks Scoring Spalling
  3. Replace any worn or poor fitting components as necessary.

Pinion and Ring Gear Inspection

  1. The ring and pinion gears are matched sets and must be replaced any time a replacement of either is necessary.
  2. Inspect the pinion and the ring gear teeth for the following conditions: Cracking Chipping Scoring Excessive wear
  3. Inspect the pinion gear splines for wear.
  4. Inspect the pinion flange splines for wear.
  5. Inspect the fit of the pinion flange on the pinion gear.
  6. Inspect the sealing surface of the pinion flange for nicks, burrs, or rough tool marks which will damage the inside diameter of the pinion seal and result in an oil leak.
  7. Inspect all of the parts for wear and replace as necessary.

Thrust Washers, Shims, and Adjuster Sleeves Inspection

  1. Inspect the shims and the thrust washers for cracks and chips. The damaged shims should be replaced with an equally sized service shim.
  2. Inspect the adjuster sleeves for damaged threads. Replace if required.

Gear Tooth Contact Pattern Inspection

The contact pattern check is not a substitute for adjusting the pinion depth and backlash. Use this method in order to verify the correct running position of the ring gear and the drive pinion. Gear sets which are not positioned properly may be noisy and/or have a short life. A pattern check ensures the best contact between the ring gear and the drive pinion for low noise and long life.

More articles — Front Drive Axle