GMC Sierra Owners Manual

Automatic Transmission Fluid (4-Speed Transmission)

When to Check and Change Automatic Transmission Fluid

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

Change the fluid and filter at the intervals listed in Maintenance Schedule on page 11‑3 and be sure to use the transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12.

How to Check Automatic Transmission Fluid

Because this operation can be a little difficult, it may be best to have this done at the dealer service department.

If not taken to the dealer, be sure to follow all the instructions here or a false reading on the dipstick could result.

Notice: Too much or too little fluid can damage the 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 checking the transmission fluid.

Wait at least 30 minutes before checking the transmission fluid level if you have been driving:
• When outside temperatures are above 32°C (90°F).
• 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 82°C to 93°C (180°F to 200°F).

Get the vehicle warmed up by driving about 24 km (15 miles) when outside temperatures are above 10°C (50°F). If it is colder than 10°C (50°F), drive the vehicle in 3 (Third) until the engine temperature gauge moves and then remains steady for 10 minutes.

A cold fluid check can be made after the vehicle has been sitting for eight hours or more with the engine off, but this is used only as a reference. Let the engine run at idle for five minutes if outside temperatures are 10°C (50°F) or more. If it is colder than 10°C (50°F), the engine may have to idle longer. Should the fluid level be low during this cold check, the fluid must be checked when hot before adding fluid. Checking the fluid hot will give you a more accurate reading of the fluid level.

Checking the Fluid Level

Prepare the vehicle as follows:

1. Park the vehicle on a level place. Keep the engine running.

2. With the parking brake applied, place the shift lever in P (Park).

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 P (Park).

4. Let the engine run at idle for three minutes or more.

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

GMS Sierra: Automatic Transmission Fluid (4-Speed Transmission). 1. Locate the transmission dipstick handle with this graphic which is located at the rear of the engine compartment, on the passenger side of the vehicle.

1. Locate the transmission dipstick handle with this graphic which is located at the rear of the engine compartment, on the passenger side of the vehicle.

See Engine Compartment Overview on page 10‑6 for more information on location.

2. Flip the handle up, then pull out the dipstick and wipe it with a clean rag or paper towel.

3. Push it back in all the way, wait three seconds and then pull it back out again.

GMS Sierra: Automatic Transmission Fluid (4-Speed Transmission). 4. Check both sides of the dipstick, and read the lower level. The fluid level must be in the COLD area, below the cross-hatched area, for a cold check or in the HOT or cross-hatched area for a hot check. Be sure to keep the dipstick pointed down to get an accurate reading.

4. Check both sides of the dipstick, and read the lower level. The fluid level must be in the COLD area, below the cross-hatched area, for a cold check or in the HOT or cross-hatched area for a hot check. Be sure to keep the dipstick pointed down to get an accurate reading.

5. If the fluid level is in the acceptable range, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place.

Consistency of Readings

Always check the fluid level at least twice using the procedure described previously. Consistency (repeatable readings) is important to maintaining proper fluid level. If readings are still inconsistent, contact the dealer.

How to Add Automatic Transmission Fluid

Refer to Recommended Fluids and Lubricants on page 11‑12 to determine what kind of transmission fluid to use.

Using a funnel, add fluid down the transmission dipstick tube only after checking the transmission fluid while it is hot. A cold check is used only as a reference. If the fluid level is low, add only enough of the proper fluid to bring the level up to the HOT area for a hot check.

It does not take much fluid, generally less than 0.5 Liter (1 Pint).

Do not overfill.

Notice: Use of the incorrect automatic transmission fluid may damage the vehicle, and the damages may not be covered by the vehicle warranty. Always use the automatic transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12.

• After adding fluid, recheck the fluid level as described under “How to Check Automatic Transmission Fluid,” earlier in this section.

• When the correct fluid level is obtained, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place.