GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Transmission Does Not Shift into One Gear

Diagnostic Aids

When the manual transmission will not transmit power from the engine to the wheels and one gear will not shift it is possible that the gear is stripped. If the transmission will not shift in all gears it is possible that the input or countershaft gears are stripped or a broken input or output shaft has occurred. Sometimes the transmission shift control may not be working correctly. You should also perform a static shift and a dynamic shift test.

Test Description

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

  1. This step checks for worn or damage shift control components.

    2.

  2. This step inspects for any problems with the hydraulic system.

    3.

  3. This step inspects for internal parts that may have worn or damaged components.

Step

Action

Yes

No

DEFINITION: The transmission does not shift into 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

Check the operation of the transmission shift lever.

Is the control worn, binding, or damaged?

Go to Step 3

Go to Step 4

3

Replace the transmission shift lever. Refer to Shift Lever Replacement .

Did you find and repair the condition?

System OK

Go to Step 4

4

Inspect the hydraulic clutch operation. Refer to Symptoms - Manual Transmission in Clutch.

Is the clutch operating properly?

System OK

Go to Step 5

5
  1. Remove the transmission. Refer to Transmission Replacement .
  2. Inspect the concentric slave cylinder for being faulty or damaged.

Is the concentric slave cylinder faulty or damage?

Go to Step 6

System OK

6

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

Did you find and repair the condition?

System OK

Go to Step 7

7

Inspect the pilot bearing and the input shaft.

Is there signs of the input shaft binding in the pilot bearing?

Go to Step 8

System OK

8
  1. Replace the clutch pilot bearing. Refer to Clutch Pilot Bearing Replacement in Clutch.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

System OK

Go to Step 9

9

Disassemble and inspect the following transmission internal components for wear or damage:

    • Gearshift components
    • Transmission gears
    • Bearings

Are any of the components worn or damaged?

Go to Step 10

System OK

10
  1. Replace all worn or damaged components. Refer to Transmission/Transaxle Unit Repair Manual.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the conditon?

Go to Step 11

Go to Diagnostic Aids

11

Operate the system in order to verify the repair.

Did you correct the conditon?

System OK

Go to Step 1