GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Transmission Locked in One Gear

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step is checking for a faulty actuator cylinder.

  2. This step is checking for a dented or damaged shift fork.

  3. This step is checking for worn or damaged internal components.

Step

Action

Yes

No

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

1

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

Go to Step 2

Go to Symptoms - Manual Transmission

2

Inspect the transmission fluid level. Refer to Fluid Replacement .

Is the transmission fluid level correct?

Go to Step 4

Go to Step 3

3

Add transmission fluid if necessary.

Did you find and repair the condition?

Go to Step 13

Go to Step 5

4

Inspect for the correct type transmission fluid.

Is the correct type transmission fluid being used?

Go to Step 6

Go to Step 5

5

Drain and refill the transmission with the correct type fluid. Refer to Fluid Replacement .

Did you find and repair the condition?

Go to Step 13

Go to Step 6

6

Inspect the clutch actuator operation. Refer to Symptoms - Clutch in Clutch.

Is the clutch actuator operating properly?

Go to Step 13

Go to Step 7

7

Replace the clutch actuator. Refer to Clutch Concentric Actuator Cylinder Replacement in Clutch.

Did you find and repair the condition?

Go to Step 13

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.

Is there a dented or damaged shift fork?

Go to Step 9

--

9

Replace the worn or damaged components as necessary.

Did you find and repair the condition?

Go to Step 10

--

10

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

Is there an incorrectly assembled or broken shift mechanism?

Go to Step 11

Go to Step 12

11
  1. Replace worn or damaged components as necessary. Refer to Transmission/Transaxle/Transfer Case Unit Repair Manual.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

Go to Step 13

Go to Step 12

12

Disassemble and inspect the transmission for a worn or damaged geartrain component.

Are there any worn or damaged geartrain components?

Go to Step 13

Go to Diagnostic Aids

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1