GM Service Manual Online
For 1990-2009 cars only

4L80-E Transmission Fluid Checking Procedure

Step

Action

Value(s)

Yes

No

DEFINITION: Diagnose transmission fluid conditions by color

1

Check the fluid color.

Is the fluid color red?

--

Go to Step 2

Go to Step 11

2

Is the fluid level satisfactory?

--

Go to Step 21

Go to Step 3

3

Check the fluid.

Is the fluid foamy?

--

Go to Step 8

Go to Step 4

4

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

Is the level high?

--

Go to Step 9

Go to Step 5

5

Fluid will be low.

Add fluid to the proper fluid level.

Is the fluid level satisfactory?

--

Go to Step 6

--

6

Check for external leaks. Refer Fluid Leak Diagnosis and Repair .

Did you find any leaks?

--

Go to Step 7

Go to Step 21

7

Correct the leak condition.

Did you correct the leak condition?

--

Go to Step 21

--

8

Is the fluid level too high?

--

Go to Step 9

Go to Step 10

9

Remove excess fluid to the proper fluid level. Refer to Fluid Changing Procedure in On-Vehicle service section.

Is the fluid level satisfactory?

--

Go to Step 21

--

10

Check for contaminants in the fluid.

Drain the fluid to determine the source of the contamination.

Did you drain the fluid?

--

Go to Step 15

--

11

Is the fluid color non-transparent pink?

--

Go to Step 12

Go to Step 13

12

Replace the cooler.

Is the replacement complete?

--

Go to Step 15

--

13

The fluid color should be light brown. Notice: Transmission fluid may turn dark with normal use. This does not always indicate oxidation or contamination.

Is the fluid color light brown?

--

Go to Step 14

--

14

Drain the fluid to determine if the fluid is contaminated.

Notice: A very small amount of material in the bottom pan is a normal condition, but large pieces of metal or other material in the bottom pan require a transmission overhaul.

Was the fluid contaminated?

--

Go to Step 15

Go to Step 18

15

Overhaul the transmission. Refer to the Unit Repair Section.

Is the overhaul complete?

--

Go to Step 16

--

16

Clear TRANS ADAPT.

Reset the oil life monitor to 100%.

Are the reset procedures complete?

--

Go to Step 17

--

17

Add new fluid.

Is the procedure complete?

--

Go to Step 20

--

18

Change the fluid and the filter.

Is this procedure complete?

--

Go to Step 19

--

19

Reset the oil life monitor to 100%.

Are the reset procedures complete?

--

Go to Step 20

--

20

Is the fluid level satisfactory? If not, correct as needed.

--

Go to Step 21

--

21

Perform the Functional Test .

Is the Functional Test completed?

--

System OK

--

Transmission Fluid Checking Procedure

    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 three seconds in each range, ending in Park.
  4. Apply the parking brake and let the engine idle for three 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 three 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.