Transfer Case Will Not Shift

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
DEFINITION: While shifting from HI range to LO range, there is gear clashing or no HI range. Or the transfer case will not shift from 2 wheel drive to 4 wheel drive. Review the Symptoms - Transfer Case and perform the necessary inspections.
Shift linkage worn	Inspect the shift linkage for correct adjustment or for being worn. Refer to Transfer Case Control Lever Replacement and Transfer Case Control Rod Replacement .
Mode shift clash	Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - NVG 261-NP2 Unit Repair. Inspect the synchronizer for being faulty. Refer to Cleaning and Inspection in Transfer Case - NVG 261-NP2 Unit Repair. Replace the synchronizer if faulty. Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair.
Mode block	Disassemble the transfer case. Refer to Transfer Case Disassemble in Transfer Case - NVG 261-NP2 Unit Repair. Inspect the synchronizer for sliding freely on the rear output shaft. Inspect the synchronizer for being faulty. Replace the synchronizer if it is faulty. Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair. If the symptoms occur during cold temperatures, flush and fill the front axle with synthetic fluid. Refer to Lubricant Level Inspection - Front Drive Axle in Front Drive Axle.
High/low range shift fork	Inspect the high/low shift fork for the following conditions: The roller on the shift fork for wear or damage Worn or melted range fork pads Cracked or bent shift fork Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair. Replace the following components if found faulty: The shift fork pads The shift fork Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair.
High/low range sleeve	Inspect the high/low range sleeve for the following conditions: Engagement teeth for burrs or damage Sliding freely on the rear output shaft The range sleeve shift fork collar for excessive wear Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair. Replace the range sleeve if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair.
Input gear needle bearing	Inspect for the following conditions: Failed needle bearing in the input gear Journal on the rear output shaft for excessive wear or damage Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair. Replace the bearing if faulty. Replace the mainshaft if damaged.
High/low planetary carrier	Inspect the high/low planetary engagement teeth for burrs or damage. Refer to Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair. Replace the range sleeve if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 261-NP2 Unit Repair.