Transfer Case Leak Diagnosis

Fluorescent Dye Method

1. Add GE 28431-6  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 GE 28428-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.
   NOTE:

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

3. Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached.
4. Shut OFF the engine.
5. Inspect the suspected leak area.
6. Trace the leak path through the powder in order to find the source of the leak.

1. Inspect for a restricted vent hose assembly. Repair as required.
2. Add J-28431-6 Fluorescent dye to the transmission to determine the source of the leak.
3. Operate the vehicle.
4. Inspect the weep hole area for a fluid leak and for traces of dye within the oil using the J-42220 High intensity black light kit.
5. If fluorescent dye is present within the fluid leak, replace the transmission rear output shaft seal.
6. If fluorescent dye is not present within the fluid leak, replace the transfer case input shaft oil seal.

   Refer to Transfer Case Disassemble , and Transfer Case Assemble .

1. Inspect for a loose, disconnected, restricted, or damaged transmission vent hose assembly.
2. Replace components as required.

1. Inspect for an under-tightened oil fill plug, a damaged fill plug seal, or damage to the rear case half sealing surface
2. Inspect for an under-tightened drain plug or incorrect type or missing sealant on the drain plug threads.

   Refer to Adhesives, Fluids, Lubricants, and Sealers .

3. Replace the oil fill plug if seal damage is present and tighten to the correct torque value.
4. Install the correct sealer onto the threads of the oil drain plug and tighten to the correct torque value.

   Refer to Transfer Case Fluid Replacement .

1. Remove the oil temperature sensor.

   Refer to Transfer Case Fluid Temperature Sensor Replacement .

2. Inspect for the following conditions:
   • Sensor cross threaded into the housing
   • Damage to the sensor seal
   • Sensor over tightened causing deformation of the sensor
   • Damage to the case half sealing surface
3. Replace components as required.

1. Inspect for a leaking rear output shaft oil seal.

   Refer to Transfer Case Disassemble , and Transfer Case Assemble .

2. Inspect the rear output flange sealing surface for excessive wear, rust, or other damage. Minor abrasions may be repaired using very fine emery cloth sandpaper.
3. Replace components as required.

1. Inspect for a leaking oil transfer tube or transfer tube fittings.
2. Replace components as required.

1. Inspect for a restricted vent hose assembly. Repair as required.
2. Inspect for a leaking front output shaft oil seal.

   Refer to Transmission-to-Transfer Case Adapter Weep Hole Leak in this table.

   Refer to Transfer Case Disassemble , and Transfer Case Assemble .

3. Inspect the front output flange sealing surface for excessive wear, rust, or other damage. Minor abrasions may be repaired using very fine emery cloth sandpaper.

   Refer to Transfer Case Disassemble , and Transfer Case Assemble .

4. Replace components as required.

1. Inspect for an incorrect low torque value on the oil pump cover bolts. Refer to Fastener Specifications .
2. Inspect for a leaking oil pump cover O-ring seal.
3. Inspect for a damage case half or cover sealing surfaces.
4. Replace components as required.

1. Inspect the rear case half at the clutch coil locations.
2. Replace the clutch coil assembly as required.

1. Inspect for a cracked case half or porosity.
2. Add J-28431-6 fluorescent Dye to the transfer case.
3. Operate the vehicle.
4. Inspect the location of the leak for presence of dye within the oil using the J-28428-E High Intensity Black Light Kit.
5. Replace components as required.