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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> Transmission >> Transfer Case - AAM >> Diagnostic Information and Procedures >> Transfer Case Leak Diagnosis

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. See below for suggested diagnostic method (s).

Special Tools

  • GE28431-6  Fluorescent Oil Dye
  • GE28428-E  High Intensity Black Light Kit
For equivalent regional tools, refer to Special Tools .

Fluorescent Dye Method

  1. Add GE28431-6  Fluorescent dye to the transmission or transfer case to determine the source of the leak.
  2. Operate the vehicle.
  3. Inspect for the presence of dye within the oil leak using the GE28428-E  High Intensity Black Light Kit. A presence or non-presence of dye within the oil leak will indicate which component is the source of the leak.

Powder Method

    CAUTION:

    Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.

  1. Thoroughly clean the suspected leak area using a rag.
  2. Apply an aerosol type leak tracing powder to the suspected leak area.
  3. NOTE:

    Do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.

  4. Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached.
  5. Shut OFF the engine.
  6. Inspect the suspected leak area.
  7. Trace the leak path through the powder in order to find the source of the leak.
Drain plug or fill plug leak
  1. Inspect for dirty, worn, scored sealing surfaces, or missing drain and/or fill plug sealing washers.
  2. Replace as required.
Restricted or damaged ventilation hose assembly Replace the ventilation hose assembly, as required.
Leaking at the transfer case left side weep hole
  • A transmission oil leak at the transfer case weep hole area is caused by the transmission right side drive shaft seal.
  • A gear oil leak at the transfer case weep hole area is caused by the transfer case input shaft front (inner) seal.
Replace components as required.
If the leak is transmission or O-ring related, do not replace the transfer case input shaft seals.
Leaking at the transfer case right side weep hole
A transmission or gear oil leak at the transfer case right side weep hole is caused by the input shaft seal located in the rear extension housing.
Replace the input shaft seal.
Leaking ATF at the right side axle shaft-to-intermediate shaft bearing location Replace the intermediate shaft seal located in the rear extension housing.
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 rear output shaft seal as required.
The O-ring is not serviceable on AAM transfer case.
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.
  • A transmission oil leak at the transfer case weep hole area is caused by the transmission right side drive shaft seal.
  • A gear oil leak at the transfer case weep hole area is caused by the transfer case input shaft front (inner) seal.
    NOTE:

    If the leak is transmission or O-ring related, do not replace the transfer case input shaft seals.

  1. Identify the type of oil leak.
  2. Replace components as required.
Case half seam leak AAM Disassemble and replace the transfer case-to-rear extension housing O-ring seal.
Leaking through case
  • Inspect for a cracked case.
  • Inspect for case porosity.