DEFINITION: A visible indication of an external fluid leak from the power transfer unit.
Review the Symptoms - Power Transfer Unit Case , and Power Transfer Unit Case Description and Operation and perform the necessary inspections. See below for suggested diagnostic method(s). |
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Special Tools
- GE-28431-6
Fluorescent Oil Dye
- GE-28428-E
High Intensity Black Light Kit
Equivalent regional tools: Special Tools Fluorescent Dye Method
- Define suspect leaking area.
- Clean the suspect oil leak area without using any type of chemical solutions and avoid using contaminated rags.
- Add GE-28431-6
Fluorescent Oil Dye to power transfer unit to determine the source of the leak through the Fill Plug using an eyedropper placing 5 ml (0.17 oz) and re-torque fill plug. Fastener Specifications
- Operate the vehicle 50 miles under city driving conditions until normal operating temperatures are reached.
NOTE:
For vehicle testing do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.
- Take the GE-28428-E
High Intensity Black Light Kit and shine in suspect oil leak area. If UV DYE is not present this indicates PTU is not leaking. Replace adjoining component.
- Clean the suspect oil leak area without using any type of chemical solutions and avoid using contaminated rags and re-test vehicle for 50 miles to confirm leak is fixed
NOTE:
For vehicle testing do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.
- Replace PTU oil. Adhesives, Fluids, Lubricants, and Sealers
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Drain plug or fill plug leak
- Damaged or broken
- Low torque
- Missing seal
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- Inspect for dirty, worn, scored sealing surfaces, or missing drain and/or fill plug sealing washers.
- Verify torque. Fastener Specifications
- Replace as required.
Follow fluorescent dye method to verify leak if needed. |
Vent Hose
Restricted or damaged ventilation hose/vent assembly |
Replace the ventilation hose/vent assembly, as required.
- Replace the ventilation hose/vent assembly, as required
- Verify no clogging/damage on vent hose
- Perform vent hose inspection and verify vent hose is seated properly onto the vent tube
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Leaking at:
- Transaxle-to-transfer case interface
- {if equipped} Transaxle-to-adapter plate interface
- {if equipped} Adapter plate-to-transfer case interface
A transmission oil leak at the interface may be caused by the O-ring seal or face seal.
NOTE:
An ATF leak at the transaxle-to-transfer case interface may be cause by the transfer case adapter seal or a damaged sealing surface. If the leak is transmission or O-ring related, do not replace the transfer case.
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- Inspect suspect area and clean all oil from the area
NOTE:
Transmission oil is red and PTU oil is yellowish brown.
- Identify the location of leak and type of fluid
- Add dye to the power transfer unit oil if UV inspection is needed
- Replace the interface seal as required
- Power transfer unit replacement is required only if sealing surface on power transfer unit is damaged
- {if equipped} Adapter plate replacement is required only if sealing surface on adapter plate case is damaged
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Leaking at the power transfer unit left side weep hole - main housing
NOTE:
An automatic transmission fluid (ATF) or transfer case gear oil leak at the weep hole in the housing is caused by the input shaft seal located in the main housing.
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Replace components as required.
Follow fluorescent dye method to verify leak if needed. |
Leaking at the power transfer unit right side weep hole - extension housing
NOTE:
An automatic transmission fluid (ATF) or transfer case gear oil leak at the weep hole in the housing is caused by the input shaft seal located in the rear extension housing.
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Replace components as required.
Follow fluorescent dye method to verify leak if needed. |
| Leaking ATF at the intermediate drive shaft seal location in the end of the extension housing. |
- Inspect suspect area and clean all oil from the area
- Inspect and replace the intermediate drive shaft as required. This seal is located in the output end of the extension housing.
- Inspect the intermediate drive shaft bearing for excessive wear. A worn intermediate drive shaft bearing may cause excessive shaft runout and seal leakage. Replace the intermediate drive shaft bearing as required.
Refer to:
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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 suspect area and clean all oil from the area
- Identify the location of leak and type of fluid
- Inspect and replace the rear output shaft seal as required.
- The O-ring is not serviceable on AAM power transfer unit.
Refer to:
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| Case half seam leak |
Disassemble and replace the power transfer unit-to-rear extension housing O-ring seal. |
| Leaking through case |
- Inspect suspect area and clean all oil from the area
- Inspect for a cracked case.
- Inspect for case porosity.
- Ensure this leak is not from the weep hole location.
- Replace components/power transfer unit as required.
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| Leak through the actuator interface to power transfer unit |
- Inspect suspect area and clean all oil from the area
- Inspect and replace the actuator assembly seal as required.
- Ensure this leak is not from the weep hole location
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| Pinion housing interface leak (main housing/pinion housing interface) |
- Inspect suspect area and clean all oil from the area
- Identify the location of leak and type of fluid
- Disassemble and replace the pinion housing O-ring seal
Refer to:
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| Cover housing leak (cover housing/extension housing interface) |
- Inspect suspect area and clean all oil from the area
- Identify the location of leak and type of fluid
- Disassemble and replace the cover housing O-ring seal
Refer to:
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