GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Transmission/Transaxle 🢒 Manual Transmission - Medium Duty 🢒 Transmission Locked in One Gear

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. A static shift test is performed by shifting into all gears with the engine not operating. By confirming that the transmission can be shifted into all positions, ensures that the shift components are not excessively worn or damaged.

    2.

  2. A dynamic shift test is performed by shifting into all of the gear positions with the engine operating. Test to ensure that the internal shift components are properly functioning.

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.

If the transmission is equipped with an air shift control, refer to the transmission manufacturer repair manual for the correct diagnosis and repair.

1

Did you review the manual transmission symptom and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Manual Transmission

2

Inspect for the correct type transmission fluid. Refer to Lubrication Specifications .

Is the correct type transmission fluid being used?

Go to Step 4

Go to Step 3

3

Drain and refill the transmission with the correct type fluid. Refer to Transmission Oil Changing .

Did you find and repair the condition?

Go to Step 10

Go to Step 4

4

  1. Perform a static shift test on the transmission.
  2. Test for the shift lever moving to all gear positions.

Were you able to shift into all positions?

Go to Step 6

Go to Step 5

5
  1. Remove the shift lever. Refer to Control Lever and/or Boot Replacement .
  2. Inspect the following shift components for wear or damage
    3. • The shift lever
    • The shift control housing

Did you find and repair the conditions?

Go to Step 10

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 8

Go to Step 7

7
  1. Remove the shift cover. Refer to the transmission manufacturer repair manual.
  2. Inspect the following shift cover components for being worn or damaged:
    3. • The internal shift levers
    • The shift rails and bushings
    • The shift forks

Did you find and repair the condition?

Go to Step 10

Go to Step 8

8
  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 in Clutch.

Did you find and repair the condition?

Go to Step 10

Go to Step 9

9

  1. Disassemble the transmission. Refer to the transmission manufacturer repair manual.
  2. Inspect the following transmission internal components for wear or damage:
    3. • 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 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1