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Home >> GMC >> 2006 >> Sierra 1500 HD, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 19 (Manual Transmission - NV 3500 - Service) >> Diagnostic Information and Procedures >> Transmission Locked in One Gear >> Test Description

Test Description

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

The numbers below refer to step numbers on diagnostic table.

  1. 2:  This step is to ensure use of proper transmission fluid. A special fluid is used to ensure proper synchronizer operation, and for sufficient lubrication. Improper fluid may cause synchronizers to stick or transmission components to overheat.
  2. 4:  A static shift test is performed by shifting into all gears with engine not operating. By confirming that transmission can be shifted into all positions, ensures that shift lever is not excessively worn or damaged.
  3. 6:  A dynamic shift test is performed by shifting into all of gear positions with engine operating. Test to ensure that internal shift components are functioning properly.
Transmission Locked in One Gear

Step Action Yes No
DEFINITION: The transmission cannot be shifted out of a gear, or the vehicle will not move because the transmission is locked.
1 Did you review the Symptoms - Manual Transmission, and perform the necessary inspections? Go to Step 2  Go to Symptoms - Manual Transmission 
2 Inspect for the correct type of transmission fluid.
Is the correct type transmission fluid being used?		 Go to Step 4  Go to Step 3 
3 Drain the transmission fluid, and fill the transmission with the correct type of fluid. Refer to Transmission Fluid Replacement .
Did you find and repair the condition?		 Go to Step 9  Go to Step 4 
4
  1. Perform a static shift test on the transmission.
  2. Test for the shift lever moving to all positions.
Were you able to shift into all positions?		 Go to Step 6  Go to Step 5 
5
  1. Remove the shift lever.
  2. Inspect for worn or faulty components. Refer to Shift Lever Assembly Replacement .
Did you find and repair the conditions?		 Go to Step 9  Go to Step 6 
6
  1. Perform a dynamic shift test on the transmission.
  2. Test for being able to shift in and out of the gear with the concern.
Were you able to shift the transmission correctly?		 Go to Step 7  Go to Step 8 
7
  1. Remove the transmission. Refer to Transmission Replacement .
  2. Inspect the clutch system for the clutch not releasing properly. Refer to Clutch System Description and Operation .
Did you find and repair the condition?		 Go to Step 9  Go to Step 8 
8
  1. Disassemble the transmission. Refer to TRANSMISSION DISASSEMBLE .
  2. Inspect the following transmission internal components for wear or damage:
    • The shift rail
    • The internal shift control lever
    • The synchronizer components for being broken or faulty
    • The speed gears for being seized to the mainshaft
Did you find and repair the conditions?		 Go to Step 9  -
9 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 1 
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