GM Service Manual Online
For 1990-2009 cars only

    Notice: Applying the brake pedal during this procedure will affect the fluid level reading.

  1. Start the engine and operate the vehicle for 15 minutes or until the transmission fluid reaches an operating temperature of 82-93°C (180-200°F).
  2. Park the vehicle on a level surface.
  3. With your foot on the brake, move the shift lever through each gear range. Pause for about 3 seconds in each range, ending in Park.
  4. Apply the parking brake and let the engine idle for 3 minutes.
  5. Remove the transmission fluid level indicator, wipe the indicator clean, and reinsert the indicator. Give the indicator a full twist to close.
  6. Wait 3 seconds and remove the indicator.
  7. Read both sides of the indicator. The fluid must be within the hot cross-hatched area using the lowest level reading.

Step

Action

Value(s)

Yes

No

1

Check the fluid life monitor.

Is the monitor life 10% or less?

--

Go to Step 16

Go to Step 2

2

Check the fluid color.

Is the fluid red in color?

--

Go to Step 6

Go to Step 3

3

Is the fluid color non-transparent pink?

--

Go to Step 18

Go to Step 4

4

Important: Transmission fluid may turn a dark brown color from normal use. This does not always indicate oxidation or contamination.

Is the fluid light brown in color?

--

Go to Step 6

Go to Step 5

5

Is the fluid black in color and/or have a burnt smell?

--

Go to Step 15

Go to Step 6

6

Does the fluid appear as solid liquid, and not foamy or full of bubbles, on the fluid level indicator?

--

Go to Step 7

Go to Step 8

7

Check the fluid level. The proper level should be in the middle of the X pattern on the fluid level indicator.

Is the fluid level satisfactory?

--

Go to Step 20

Go to Step 8

8

Is the fluid level high on the indicator?

--

Go to Step 13

Go to Step 9

9

Is the fluid level low on the indicator?

--

Go to Step 10

Go to Step 5

10

Check for external leaks. Refer to Fluid Leak Diagnosis .

Did you find an external leak?

--

Go to Step 11

Go to Step 12

11

Repair the leaks as needed.

Are any leaks still present?

--

Go to Step 10

Go to Step 12

12

Add fluid until the level of the fluid is in the middle of the X pattern on the fluid level indicator.

Is the fluid level satisfactory?

--

Go to Step 20

Go to Step 7

13

Drain the fluid until the fluid level is in the middle of the X mark on the fluid level indicator.

Is the fluid level satisfactory?

--

Go to Step 20

Go to Step 7

14

  1. Replace the oil cooler.
  2. Flush the oil cooler lines.
  3. Refer to Transmission Fluid Cooler Flushing and Flow Test .

Did you complete the replacement?

--

Go to Step 16

--

15

    Important: A small amount of friction material in the bottom of the pan is a normal condition. Large pieces of material and/or metal particles may require a complete transmission overhaul.

  1. Drain the transmission fluid.
  2. Inspect the oil pan.

Are there signs of internal component damage in the bottom of the transmission oil pan?

--

Go to Step 17

Go to Step 14

16

Replace the transmission fluid and filter. Refer to Auxiliary Control Valve Body Cover, Fluid Filter Seal, and Filter Removal .

Did you complete the replacement?

--

Go to Step 7

--

17

Flush the oil cooler and the lines. Refer to Transmission Fluid Cooler Flushing and Flow Test .

Did you complete the Automatic Transmission Oil Cooler Flushing and Flow Test?

--

Go to Step 19

--

18

Overhaul the transmission.

Is the Transmission Overhaul Procedure complete?

--

Go to Step 19

--

19

Add new transmission fluid.

Did you add new transmission fluid?

--

Go to Step 7

--

20

Check the fluid level and correct as necessary.

Is the fluid level satisfactory?

--

Go to Step 21

--

21

If equipped, reset the oil life monitor to 100%.

Are all of the reset procedures complete?

--

System OK

--