GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

The manual transmission can be noisy for a number of reasons. It can be noisy in neutral, low, high, and/or reverse gear. Diagnose the transmission, including the level of fluid and the correct type of fluid in the transmission. Inspect for misalignment or loose bolts to the engine. The transmission could be noisy internally. Gears, synchronizers, and bearings should be inspected for worn or damaged components. These are only a few areas that may cause the transmission to be noisy. You should inspect all possibilities that could lead you to the noise of these concerns.

Test Description

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

  1. This step inspects for the correct fluid level.

  2. This step inspects for the correct type of transmission fluid.

  3. This step is inspects for internal damage or worn components.

Step

Action

Yes

No

DEFINITION: The transmission is noisy and the noise carries into the passenger compartment.

1

Did you review the Symptoms - Manual Transmission operations and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Manual Transmission

2

Inspect the transmission fluid level.

Is the fluid level correct?

Go to Step 4

Go to Step 3

3

Add transmission fluid. Refer to Transmission Fluid Replacement .

Is the transmission noisy?

Go to Step 4

System OK

4

Inspect the transmission for the correct type of fluid.

Is the transmission fluid the correct type?

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 shift control closeout boot.

Is the closeout boot loose or damaged?

Go to Step 7

Go to Step 8

7

Position and tighten the shift tower to specification or replace the shift control closeout boot, as necessary. Refer to Transmission Control Replacement .

Did you find and repair the condition?

System OK

Go to Step 8

8

Inspect the clutch housing for loose bolts and/or misalignment with the engine.

Did you find any loose bolts or misalignment with the engine?

Go to Step 9

Go to Step 10

9

Inspect the shift tower boot.

Is the closeout boot loose or damaged?

Go to Step 10

Go to Step 11

10

  1. Remove the transmission. Refer to Transmission Replacement .
  2. Disassemble and inspect the following transmission components for wear or damage:
  3. • Gear shift
    • Transmission gears
    • Bearings

Did you find any wear or damage?

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