Diagnostic Starting Point - Transfer Case
Begin the system diagnosis by reviewing the Transfer Case Disassembled View and the Transfer Case Description and Operation . Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Transfer Case in order to identify the correct procedure for diagnosing the system and where the procedure is located.
Strategy Based Diagnostics
Review the system operations in order to familiarize yourself with the system functions. Refer to Transfer Case Disassembled View and Transfer Case Description and Operation . All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system condition. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis in General Information.
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the vehicle. Refer to «Checking Aftermarket Accessories»(ref-188770-S05143345352005090200000) in Wiring Systems.
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
- Check for the correct lubricant levels and the proper viscosities.
- Verify the exact operating conditions under which the concern exists. Note factors such as vehicle speed, road conditions, ambient temperature, and other specifics.
- Compare the driving characteristics or sounds, if applicable, to a known good vehicle and ensure you are not trying to correct a normal condition.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- «Diagnostic Starting Point - Vibration Diagnosis and Correction»(ref-188832-S01535877352005090200000) in Vibration Diagnosis and Correction
- «Diagnostic Starting Point - Transfer Case»(ref-188836-S11444011512005090200000)
- «Diagnostic Starting Point - Rear Drive Axle»(ref-188834-S39295956112005090200000) in Rear Drive Axle
- «Diagnostic Starting Point - Wheel Drive Shafts»(ref-188827-S15496421052005090200000) in Wheel Drive Shafts
- «Diagnostic Starting Point - Propeller Shaft»(ref-188830-S39979025742005090200000) in Propeller Shaft
- «Noisy in Drive»(ref-188836-S15454944342005090200000)
- «Noisy When Coasting»(ref-188836-S05441039382005090200000)
- «Intermittent Noise»(ref-188836-S24669764822005090200000)
- «Constant Noise»(ref-188836-S38885871932005090200000)
- «Transfer Case Leak Diagnosis»(ref-188836-S13945617012005090200000)
Transfer Case Leak Diagnosis
| Cause | Correction |
|---|---|
| Restricted or damaged ventilation valve or hose | Repair or replace as required. |
| Worn, scored, or missing drain and/or fill plug sealing washers | Install new sealing washers and tighten the plugs per specifications. |
| Worn or damaged input or output shaft oil seals | Replace the oil seals as required. |
| Cut or damaged side cover O-ring seal | Replace the O-ring seal as required. |
| Case or cover porosity or leaking seal surfaces | Replace the transfer case as required. |
Transfer Case Leak Diagnosis
Transfer Case Assembly Inspection
Tools Required
SA9179NE Dial Indicator. See Special Tools and Equipment .
- Use the SA9179NE in order to measure the output shaft/input gear backlash. See «Special Tools and Equipment»(ref-188836-S04359754522005090200000) . Specification: 0.06-0.16 mm (0.0024-0.0063 in)
- Secure the case in a bench vise with soft jaws.
- Measure the output shaft/input gear rotating torque. Specification: 3.20-4.16 mm (28.2-34.3 lb in)
- If the measurements are not within specifications, replace the transfer case as required.
Transfer Case Housings Cleaning and Inspection
- Inspect the case (100) for the following conditions: Damaged sealing surfaces Damaged bolt hole threads Worn or scored bearing race bores Loose or restricted ventilation tube Porosity Damage to the exterior of the case
- Inspect the cover (101) for the following conditions: Damaged sealing surfaces Worn or scored bearing race bore Porosity Damage to the exterior of the cover
Internal Components Cleaning and Inspection
- Inspect the output shaft (201) for the following conditions: Worn or damaged splines Damaged threads Excessive wear or scoring on the sealing surface Worn gear teeth
- Inspect the input gear (214) for the following conditions: Worn or damaged splines Excessive wear or scoring on the sealing surface Worn gear teeth
- Inspect the bearing rollers and races for the following conditions: Pitting Scoring or grooves Excessive wear or heat discoloration
- Inspect the bearings for bent roller cages.