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 indicator clean. Reinsert the indicator. Give the indicator a full twist in order 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.

Transmission Fluid Checking Procedure

Step

Action

Yes

No

1

Check the fluid color.

Is the fluid red in color?

Go to Step 5

Go to Step 2

2

Is the fluid a non-transparent pink in color?

Go to Step 14

Go to Step 3

3

Important: Fluid may turn a dark brown in color from normal use. This does not always indicate an oxidation or a contamination issue.

Is the fluid a light brown in color?

Go to Step 5

Go to Step 4

4

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

Go to Step 14

Go to Step 5

5

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

Go to Step 6

Go to Step 6

6

Check the fluid level. Proper level should be in middle of the "X" pattern, on level indicator.

Is the level OK?

Go to Step 19

Go to Step 7

7

Is the fluid level high on indicator?

Go to Step 12

Go to Step 8

8

Is the fluid level low on indicator?

Go to Step 9

Go to Step 4

9

Check for any external leak or leaks. Refer to Fluid Leak Diagnosis .

Did you find an external leak or leaks?

Go to Step 10

Go to Step 11

10

Correct leak or leaks as needed. Are any leak or leaks still present?

Go to Step 9

Go to Step 11

11

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

Is the level OK?

Go to Step 19

Go to Step 6

12

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

Is level OK?

Go to Step 19

Go to Step 6

13

Replace oil cooler and flush lines.

Is the replacement complete?

Go to Step 15

--

14

Important: A small amount of "friction" material in pan bottom is a "normal" condition, but large pieces and or metal particles will require complete transmission overhaul.

Drain fluid and remove oil pan to inspect.

Is there sign or signs of internal component damage noted in bottom of transmission oil pan?

Go to Step 16

Go to Step 13

15

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

Is the replacement complete?

Go to Step 6

--

16

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

Is the Automatic Transmission Oil Cooler Flushing and Flow Test complete?

Go to Step 17

--

17

Overhaul transmission. Refer to the 4L60-E/4L65-E section of the Transmission Unit Repair Manual.

Is the Transmission Overhaul Procedure complete?

Go to Step 18

--

18

Add new fluid.

Is the procedure complete?

Go to Step 6

--

19

Check the fluid level and correct as necessary.

Is the fluid level satisfactory?

System OK

Go to Step 1