GM Service Manual Online
For 1990-2009 cars only
  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 fluid level indicator clean. Insert the fluid level indicator. Give the fluid level indicator a full twist in order to close.
  6. Wait 3 seconds and remove the fluid level indicator.
  7. Read both sides of the fluid level indicator. The fluid must be within the hot cross-hatched area using the lowest level reading.

Step

Action

Yes

No

DEFINITION: Diagnose transmission fluid conditions by color.

1

Inspect the transmission fluid color.

Is the transmission fluid color red?

Go to Step 2

Go to Step 11

2

Is the transmission fluid level satisfactory?

System OK

Go to Step 3

3

Inspect the transmission fluid.

Is the transmission fluid foamy?

Go to Step 8

Go to Step 4

4

Measure the transmission fluid level. The proper fluid level should be in the middle of the X-hatch.

Is the transmission fluid level high?

Go to Step 9

Go to Step 5

5

The transmission fluid is low. Add fluid to the proper level.

Is the transmission fluid level satisfactory?

Go to Step 6

--

6

Inspect for external leaks. Refer to Fluid Leak Diagnosis.

Did you find any leaks?

Go to Step 7

Go to Step 20

7

Repair the leak condition.

Did you repair the leak condition?

Go to Step 20

--

8

Is the transmission fluid level high?

Go to Step 9

Go to Step 10

9

Remove excess transmission fluid to the proper level. Refer to Automatic Transmission Fluid and Filter Replacement.

Is the transmission fluid level satisfactory?

Go to Step 20

--

10

  1. Inspect for contaminants in the transmission fluid.
  2. Drain the transmission fluid in order to determine the source of the contamination.

Did you drain the transmission fluid?

Go to Step 15

--

11

Is the transmission fluid color non-transparent pink?

Go to Step 12

Go to Step 13

12

Replace the cooler.

Did you complete the replacement?

Go to Step 15

--

13

Note: Transmission fluid may turn dark with normal use. This does not always indicate oxidation or contamination.

The transmission fluid color should be light brown.

Is the transmission fluid color light brown?

Go to Step 14

--

14

Note: A very small amount of material in the bottom pan is a normal condition. Large pieces of metal or other material in the bottom pan require a transmission overhaul.

Drain the transmission fluid in order to determine if the transmission fluid is contaminated.

Is the transmission fluid contaminated?

Go to Step 15

Go to Step 18

15

Perform root cause and repair, as necessary.

Did you complete the repair?

Go to Step 16

--

16

Clear TRANS ADAPT.

Did you complete the reset procedures?

Go to Step 17

--

17

Add new transmission fluid.

Did you add new transmission fluid?

Go to Step 20

--

18

Replace the transmission fluid and filter. Refer to Automatic Transmission Fluid and Filter Replacement.

Did you complete the replacement?

Go to Step 19

--

19

Did you complete the reset procedures?

Go to Step 20

--

20

Is the transmission fluid level satisfactory?

System OK

Go to Step 1