Transfer Case Leak Diagnosis. Chevrolet Blazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2002 🢒 Blazer - 4WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 236/246-NP8 (Two Speed Automatic) 🢒 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.

Rear output shaft seal leaking

•	Replace the rear output shaft seal. Refer to Rear Output Shaft Seal Replacement .

•	Inspect the slip yoke seal surface for wear or pitting. Replace the slip yoke seal if the surface could cause leakage.

•	Inspect the rear bushing for wear. Replace the bushing if it is worn.

Speed sensor leaking

Replace the O-ring seal on the speed sensor. Refer to Transfer Case Speed Sensor Replacement .

Front output shaft seal leaking

•	Replace the front output shaft seal. Refer to Front Output Shaft Seal Replacement .

•	Inspect the front output shaft seal journal for wear. Replace the front output shaft if it is worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

•	Inspect the seal bore for damage. Replace the front case half if the seal bore is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

Leaking at the vent tube

•	Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement .

•	Inspect the transmission fluid level. Refer to Transmission Fluid Check in Automatic Transmission 4L60-E or Fluid Replacement in Manual Transmission NV 3500.

•	If the transmission fluid level is low, and the transfer case level is too high, replace the transfer case front input shaft seal. Refer to Input Shaft Seal Replacement .

•	Inspect the front input shaft seal surface for wear or damage.

•	Replace the front input shaft if the seal journal is worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

•	Reseal the vent tube with the correct sealer. Refer to Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

Motor/encoder area leak

•	Inspect the motor/encoder insulator for cracks. Replace the motor/encoder if the insulator is cracked. Refer to Transfer Case Motor/Encoder Replacement .

•	Inspect for a faulty actuator lever shaft bearing. Replace the control actuator lever shaft if the bearing or seal surface is faulty. Replace the bearing if it is faulty. Refer to Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

Transfer case to transmission area leak

•	Inspect the front input shaft seal for leaking. Replace the front input shaft seal if it is faulty. Refer to Input Shaft Seal Replacement .

•	Inspect the front input shaft seal surface for wear or damage.

•	Inspect the front case seal bore for damage.

•	Inspect for the input gear bore seal leaking. Replace the input gear bore seal if it is leaking. Refer to Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.

•	Inspect the transmission adapter gasket for leaking. Replace the transmission adapter gasket if it is faulty. Refer to Transfer Case Assembly Replacement .

Front case half to rear case half seam leak

Disassemble, and reseal the case halves. Refer to Transfer Case Assemble in the Transmission/Transaxle/Transfer Case Unit Repair Manual.