GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Sierra Denali 🢒 Transmission 🢒 Manual Transmission - Tremec 5-Speed (TZ0) 🢒 Transmission Locked in One Gear

Diagnostic Aids

If the transmission is locked, engaging the clutch will stop the engine. If the shift control components and the clutch system operations are operating properly, the condition is caused by internal damage, such as a dented or damaged shift fork. The transmission must be removed from the vehicle for repairs. You should also perform a static shift test and dynamic shift test.

Test Description

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

  1. This step inspects for a faulty actuator cylinder.

    2.

  2. This step inspects for a dented or damaged shift fork.

Step

Action

Yes

No

DEFINITION: The transmission cannot be shifted out of a gear.

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 transmission fluid level. Refer to Transmission Fluid Replacement .

Is the transmission fluid level correct?

Go to Step 4

Go to Step 3

3

Add transmission fluid, if necessary.

Can you shift the transmission out of gear?

System OK

Go to Step 5

4

Inspect for the correct type of transmission fluid.

Is the correct type of transmission fluid being used?

Go to Step 6

Go to Step 5

5

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?

System OK

Go to Step 6

6

Inspect the concentric slave cylinder operation. Refer to Symptoms - Clutch .

Is the clutch actuator operating properly?

Go to Step 8

Go to Step 7

7

Replace the concentric slave cylinder. Refer to Clutch Actuator Cylinder Replacement .

Did you find and repair the condition?

System OK

Go to Step 8

8

  1. Remove the transmission. Refer to Transmission Replacement .
  2. Disassemble and inspect the transmission for a dented or damaged shift fork.

Did you find a dented or damaged shift fork?

Go to Step 9

Go to Step 10

9
  1. Replace worn or damaged components, as necessary.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

System OK

Go to Step 10

10

Disassemble and inspect the transmission for an incorrectly assembled or broken shift mechanism.

Did you find an incorrectly assembled or broken shift mechanism?

Go to Step 11

System OK

11
  1. Replace worn or damaged components, as necessary.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

Go to Step 12

Go to Diagnostic Aids

12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1