Strategy Based Diagnostics
Review the system operations in order to familiarize yourself with the system functions. Refer to Transfer Case Disassembled View ,, Transfer Case Description and Operation ,, and Rear Drive Axle 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 .
Visual/Physical Inspection
- Inspect for aftermarket devices, which could affect the operation of the vehicle. Refer to «Checking Aftermarket Accessories»(ref-491170-S38135034022012073000000) .
- Inspect the easily accessible or visible system components for obvious damage or conditions, which could cause the symptom.
- Inspect 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 System Check - Vehicle»(ref-491140-S24065023222012073000000)
- «Noisy in Drive»(ref-491200-S04204894032012073000000)
- «Noisy When Coasting»(ref-491200-S41079278422012073000000)
- «Intermittent Noise»(ref-491200-S27982859642012073000000)
- «Constant Noise»(ref-491200-S08931494542012073000000)
- «Transfer Case Leak Diagnosis»(ref-491200-S19280871182012073000000)
Transfer Case Leak Diagnosis
| Cause | Correction |
|---|---|
| Drain and fill the unit with new oil with ultraviolet dye GE-28431-6 Fluorescent Oil Dye - 6 1-oz before using the GE-28428-E/J-4220 High-Intensity Black Light Kit, when inspecting for leaks. For equivalent regional tools, refer to Special Tools . | |
| Drain plug or fill plug leak | Inspect for dirty, worn, scored sealing surfaces, or missing drain and/or fill plug sealing washers. Replace as required. Refer to Transfer Case Fluid Replacement . |
| Restricted or damaged ventilation assembly | Replace the ventilation assembly, as required. |
| Leaking at the transfer case left side weep hole A transmission oil leak at the transmission-to-transfer case interface or weep hole area may be caused by the transmission to transfer case O-ring seal or transmission right side drive shaft seal. A gear oil leak at the transmission-to-transfer case interface or weep hole area is caused by the transfer case input seal. | Replace components as required. Refer to Transfer Case Disassemble , and Transfer Case Assemble . If the leak is transmission or O-ring related, do not replace the transfer case input seal. |
| Leaking at the transfer case right side weep hole A transmission oil leak at the transfer case right side weep hole is caused by the intermediate drive shaft seal. A gear oil leak at the transfer case right side weep hole is caused by the right side input seal. | Identify the type of oil leak. Replace components as required. |
| Leaking at rear output shaft area A leak at rear output shaft area is caused by either the rear output shaft seal or the rear output shaft housing O-ring seal. | Inspect and replace the O-ring or rear output shaft seal as required. |
| Leaking at transaxle assembly-to-transfer case interface A transmission oil leak at the transmission-to-transfer case interface may be caused by the transmission to transfer case O-ring seal or the transmission right side drive shaft seal. | Identify the type of oil leak. NOTE: If the leak is transmission or O-ring related, do not replace the transfer case input seal. Replace components as required. |
| Case half seam leak | Disassemble and replace transfer case seal. Refer to Transfer Case Disassemble , and Transfer Case Assemble . |
| Leaking through case | Inspect for a cracked case. Inspect for case porosity. Replace the transfer case. |
| NOTE |
|---|
| If the leak is transmission or O-ring related, do not replace the transfer case input seal. |
Transfer Case Leak Diagnosis