GM Service Manual Online
For 1990-2009 cars only

When to Check and Change Automatic Transmission Fluid

A good time to check your automatic transmission fluid level is when the engine oil is changed.

Check the fluid in the transmission and differential at the intervals listed in Part A: Scheduled Maintenance Services , and be sure to use the transmission fluid listed in Part D: Recommended Fluids and Lubricants .

How to Check Automatic Transmission Fluid

Because this operation can be a little difficult, you may choose to have this done at the dealer/retailer service department.

If you do it yourself, be sure to follow all the instructions here, or you could get a false reading on the dipstick.

Notice: Use of the incorrect automatic transmission fluid may damage your vehicle, and the damages may not be covered by your warranty. Always use the automatic transmission fluid listed in Part D: Recommended Fluids and Lubricants .

Wait at least 30 minutes before checking the transmission fluid level if you have been driving:

    • When outside temperatures are above 90°F (32°C).
    • At high speed for quite a while.
    • In heavy traffic -- especially in hot weather.
    • While pulling a trailer.

To get the right reading, the fluid should be at normal operating temperature, which is 158°F to 176°F (70°C to 80°C).

Get the vehicle warmed up by driving about 15 miles (24 km) when outside temperatures are above 50°F (10°C). If it is colder than 50°F (10°C), you may have to drive longer.

Checking the Fluid Level

Prepare your vehicle as follows:

  1. Park your vehicle on a level place. Keep the engine running.
  2. With the parking brake applied, place the shift lever in PARK (P).
  3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about three seconds in each range. Then, position the shift lever in PARK (P).
  4. Let the engine run at idle for three to five minutes.

Then, without shutting off the engine, follow these steps:

The automatic transmission dipstick has an orange handle and is located near the front of the engine compartment. See Engine Compartment Overview for more information on location.

  1. Release the tab and pull out the dipstick and wipe it with a clean rag or paper towel.
  2. Push it back in all the way, wait three seconds and then pull it back out again.

  3. Object Number: 881741  Size: G9
  4. Check both sides of the dipstick, and read the lower level. The fluid level must be between the two dimples in the hot range.
  5. If the fluid level is in the acceptable range, push the dipstick back in all the way; then press the tab down to lock the dipstick in place.

How to Add Automatic Transmission Fluid

Refer to the Maintenance Schedule to determine what kind of transmission fluid to use. See Part D: Recommended Fluids and Lubricants .

If the fluid level is low, add only enough of the proper fluid to bring the level into the area between dimples on the dipstick.

  1. Pull out the dipstick.
  2. Using a long-neck funnel, add enough fluid at the dipstick hole to bring it to the proper level.
  3. It does not take much fluid, generally less than one pint (0.5 L). Do not overfill.

    Notice: Too much or too little fluid can damage your transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too little fluid could cause the transmission to overheat. Be sure to get an accurate reading if you check your transmission fluid.

  4. After adding fluid, recheck the fluid level as described under "How to Check Automatic Transmission Fluid," earlier in this section.
  5. When the correct fluid level is obtained, push the dipstick back in all the way; then press the tab down to lock the dipstick in place.