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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 Shifts Hard >> 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. 3:  A static shift test is performed by shifting into all of gear positions with engine not operating. While performing test one should note how shift lever movement is felt. Also while shifting from one gear to other feel for binding in shift rails. You should be able to feel detent plungers operating when coming out of a gear and going into a gear.
  2. 5:  A dynamic shift test is performed by shifting into gear positions with engine operating. Test for correct mesh of synchronizers and for clutch releasing correctly. When shifting into and out of a gear, feel for shift detent plungers and for synchronizers sleeve for moving freely.
  3. 7:  transmission uses a synthetic transmission fluid that allows proper synchronizer operation. incorrect fluid may cause hard shifting by varnish build up, or not enough lubrication for proper synchronizer operation.
Transmission Shifts Hard

Step Action Yes No
DEFINITION: The transmission does not shift smoothly, or without difficulty, from one gear to the other.
1 Did you review the Symptoms - Manual Transmission, and perform the necessary inspections? Go to Step 2  Go to Symptoms - Manual Transmission 
2 Inspect the clutch system for proper operation. Refer to Clutch System Description and Operation .
Did you find or repair the condition?
Go to Step 11  Go to Step 3 
3
  1. Perform a static shift test on the transmission.
  2. Test for the following:
    • Blockage preventing full shift lever movement
    • Excessive movement in the shift lever
    • Binding in the shift lever
    • Detent plungers or shift rails binding
Are you able to shift into all gears?
Go to Step 5  Go to Step 4 
4 Remove the shift tower and inspect for worn or faulty components. Refer to Shift Lever Assembly Replacement .
Did you find and repair the condition?
Go to Step 11  Go to Step 5 
5
  1. Perform a dynamic shift test on the transmission.
  2. Test for the following:
    • Detent plungers or shift rails binding
    • Synchronizer sleeve binding
    • Gear clash into only one gear
    • Gear clash into all gears
Did the transmission shift hard into all gears?
Go to Step 6  Go to Step 10 
6 Inspect the transmission for the correct fluid level and the correct type of transmission fluid. Refer to Transmission Fluid Replacement .
Is the transmission at the correct level and proper fluid being used?
Go to Step 8  Go to Step 7 
7 Drain 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 11  Go to Step 8 
8
  1. Remove the transmission. Refer to Transmission Replacement .
  2. Inspect the clutch pressure plate and/or clutch driven plate.
Is the clutch pressure plate and/or clutch driven plate worn or faulty?
Go to Step 9  Go to Step 10 
9 Replace the clutch assembly. Refer to Clutch Assembly Replacement .
Did you find and repair the condition?
Go to Step 11  Go to Step 10 
10
  1. Disassemble the transmission. Refer to TRANSMISSION DISASSEMBLE .
  2. Inspect the following components for being faulty, in the gear that is hard to shift or clashing:
    • Excessive synchronizers blocking ring to gear clearance
    • Synchronizer hub external splines worn or damaged
    • Excessive axial clearance in the speed gear
    • Mainshaft to speed gear bearing or journal worn
    • Shift rail and the internal shift control lever components for wear or damage
  3. Replace worn or damaged components as necessary.
Did you find and repair the condition?
Go to Step 10  Go to Diagnostic Aids 
11 Operate the system in order to verify the repair.
Did you correct the condition?
System OK Go to Step 1