Diagnostic Starting Point - Transfer Case
Begin the system diagnosis by reviewing the Symptoms - Transfer Case . The Symptoms - Transfer Case will provide the following information
- The required visual/physical inspections
- The list of symptoms
Use the Strategy Based Diagnosis in General Information in order to identify the correct procedure for diagnosing the system.
Strategy Based Diagnostics
Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation .
Visual/Physical Inspection
- Inspect the easily accessible or visible system components for obvious damage, or for conditions which could cause the symptom.
- Inspect the transfer case for the proper fluid. Refer to «Transfer Case Fluid Replacement»(ref-197622-S03812431152005101200000) .
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- «Transfer Case Popping Noise»(ref-197622-S32599240072005101200000)
- «Transfer Case Whine or Rumble Noise»(ref-197622-S17578123672005101200000)
- «Transfer Case Growl or Grinding Noise»(ref-197622-S19199781352005101200000)
- «Transfer Case Shudder or Binding»(ref-197622-S04599394812005101200000)
- «Transfer Case Clunk during Acceleration and Deceleration»(ref-197622-S13311837572005101200000)
- «Transfer Case Leak Diagnosis»(ref-197622-S01839525642005101200000)
Transfer Case Leak Diagnosis
| Cause | Correction |
|---|---|
| DEFINITION: A visible indication of an external fluid leak from the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections. | |
| Drain plug or fill plug leak | Inspect for the correct sealer and the correct amount of sealer on the plugs. Install the plugs correctly. Refer to Transfer Case Fluid Replacement . |
| Rear output shaft seal leaking | Inspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Replace the rear case half if the bushing is worn. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the rear case half if the seal bore is damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the rear output shaft seal. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. |
| Front output shaft seal leaking | Inspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Replace the front case half if the seal bore is damaged. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. Replace the front output shaft seal. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. |
| Leaking at the vent | Leaking vent or input seal will be noticed from a weep hole between the adapter and the transfer case. Transfer case overfilled Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement . Damaged O-ring on vent Transmission output shaft seal leak will be noticed from a weep hole between the adapter and the transfer case. |
| Transfer case-to-adapter leak | Inspect for the following conditions: Loose mounting fasteners Gasket or sealant faulty The transfer case input shaft seal leaking Damaged O-ring on vent Repair or replace the following components if found faulty: Replace the transfer case input shaft seal. Refer to Transfer Case Input Shaft Seal Replacement . Inspect for the following: Seal improperly installed, worn, or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved, or damaged Repair or replace the loose fasteners. Replace the transfer case gasket or sealer. Repair or replace the following components if found faulty: Leaking transmission output seal Remove transfer case. Refer to Transfer Case Assembly Replacement . Leaking adapter gasket and seal Replace adapter gasket and seal. Refer to Extension Housing and Seal Replacement in Automatic Transmission - 5L40-E/5L50-E. |
| Front case half-to-rear case half seam leak | Disassemble and seal the case halves. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. |
| Case leaking | Inspect for a cracked case or case porosity. Replace the faulty case half. Refer to TRANSFER CASE DISASSEMBLE and TRANSFER CASE ASSEMBLE in Transfer Case - Overhaul - BW 4476/79 - STS. |
Transfer Case Leak Diagnosis