GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

The manual transmission can be noisy for many reasons, in neutral, low, high and reverse gear. Diagnosis the transmission by the level of fluid and the correct type of fluid in the transmission. If the transmission is in neutral, engaged, makes whirring kind of a noise, and is heard outside the vehicle, this a normal condition for this type of manual transmission. The transmission could also have internal noise from the gears, synchronizers, and bearings. They should be inspected for worn or damaged parts.

Test Description

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

  1. This step tests for the correct fluid level.

  2. This step inspects for the correct transmission fluid.

  3. This step inspects for internal damage or worn parts.

Step

Action

Yes

No

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

1

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

Go to Step 2

Go to Symptoms - Manual Transmission

2

Test 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 Level Inspection .

Did you find and repair the condition?

System OK

Go to Step 4

4

Inspect the transmission for the correct fluid type.

Is the transmission the correct type?

Go to Step 6

Go to Step 5

5

Drain and refill the transmission with the correct type 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 closeout boot to specification, or replace the boot as necessary. Refer to Shift Control Shift Closeout Boot 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.

Is there any loose bolts or misalignment with the engine?

Go to Step 9

Go to Step 10

9

Tighten the clutch housing bolts to specifications. Refer to Clutch Housing Replacement .

Did you find and repair the condition?

System OK

Go to Step 10

10

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

Is there any wear or damage?

Go to Step 11

--

11

  1. Replace worn or damaged components as necessary.
  2. Refer to Transmission Disassemble in the Transmission Unit Repair Manual.

  3. 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