Transfer Case Leak Diagnosis

WARNING: This page is about a different variant/trim than selected.

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 GE 28431-6 Fluorescent Oil Dye GE 28428-E High Intensity Black Light Kit For equivalent regional tools, refer to Special Tools . Fluorescent Dye Method Add GE 28431-6 Fluorescent dye to the transmission or transfer case to determine the source of the leak. Operate the vehicle. 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. Thoroughly clean the suspected leak area using a rag. 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. Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached. Shut OFF the engine. Inspect the suspected leak area. Trace the leak path through the powder in order to find the source of the leak.
Drain plug or fill plug leak	Inspect for the correct sealer and the correct amount of sealer on the plugs. Install the plugs correctly. Refer to Transfer Case Fluid Replacement .
Rear output shaft seal leaking	Inspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Rear output shaft bushing for excessive wear Slip yoke seal surface for wear or pitting Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Clean, or properly route the vent hose. Replace the slip yoke if the surface could cause leakage. Refer to Rear Propeller Shaft Replacement . Replace the rear case half if the bushing is worn. Refer to Transfer Case Disassemble , and Transfer Case Assemble . Replace the rear case half if the seal bore is damaged. Refer to Transfer Case Disassemble , and Transfer Case Assemble . Replace the rear output shaft seal. Refer to Rear Output Shaft Seal Replacement .
Front output shaft seal leaking	Inspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Repair or replace the following components if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Clean or properly route the vent hose. Replace the front case half if the seal bore is damaged. Refer to Transfer Case Disassemble , and Transfer Case Assemble . Replace the front output shaft seal. Refer to Front Output Shaft Seal Replacement .
Leaking at the vent	Transfer case overfilled Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement . Inspect the transmission fluid level. Refer to Transmission Fluid Level and Condition Check . If the transmission fluid level is low, and the transfer case fluid level is too high, replace the transfer case input shaft seal. Refer to Input Shaft Seal Replacement . Inspect for the following conditions: Seal improperly installed, worn, or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved, or damaged Seal the vent with the correct sealer if leaking at the case. Refer to Transfer Case Assemble .
Transfer case to adapter leak	Inspect for the following conditions: Loose mounting fasteners Gasket or sealant faulty The transfer case input shaft seal leaking Repair or replace the following components if found faulty: Replace the transfer case input shaft seal. Refer to Input Shaft Seal Replacement . Inspect for the following: Seal improperly installed, worn, or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved, or damaged Repair or replace the loose fasteners. Refer to Transfer Case Adapter Replacement . Replace the transfer case gasket or sealer. Refer to Transfer Case Adapter Replacement .
Front case half to rear case half seam leak	Disassemble and seal the case halves. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Case leaking	Inspect for a cracked case or case porosity. Replace the faulty case half. Refer to Transfer Case Disassemble , and Transfer Case Assemble .