Symptoms - Transfer Case. GMC Truck Envoy

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2002 🢒 Envoy - 4WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 226-NP8 🢒 Symptoms - Transfer Case

Important:

Perform the Diagnostic System Check - Transfer Case before using the symptom tables, in order to verify that the following statements are true:

•	DTCs are not set.

•	The control modules can communicate via the serial data link.

Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation .

•	Inspect for aftermarket devices which could affect the operation of the automatic transfer case system. Refer to Checking Aftermarket Accessories in Wiring Systems.

•	Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

•	Inspect the automatic transfer case for the proper fluid level.

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

•	Front Axle Will Not Engage

•	Front Axle Will Not Disengage

•	Transfer Case Shift Control Switch Inoperative

•	No Correction for Slip in All-Wheel Drive Mode

•	Transfer Case Shift Control Switch Indicator Always On - Two or More

•	Transfer Case Shift Control Switch Indicator Flashes, then Returns to Previous Mode

•	Transfer Case Shift Control Switch Indicators Flash Continuously 15 Seconds or More

•	Transfer Case Shift Control Switch Indicator Inoperative - One or More

•	Service Indicator Always On

•	Service Indicator Inoperative

•	Transfer Case Popping Noise

•	Transfer Case Whine or Rumble Noise

•	Transfer Case Growl or Grinding Noise

•	Transfer Case Grating Noise

•	Transfer Case Clunk in 2HI Only

•	Transfer Case Clunk in 4HI

•	Transfer Case Clunk in 4LO

•	Transfer Case Shudder or Binding

•	Transfer Case Leak Diagnosis