GMC Sierra Owners Manual

Automatic Transmission Fluid (6-Speed Transmission)
Vehicle Care / Vehicle Checks / Automatic Transmission Fluid (6-Speed Transmission)

When to Check and Change Automatic Transmission Fluid

It is usually not necessary to check the transmission fluid level.

The only reason for fluid loss is a transmission leak or overheated transmission. If a small leak is suspected, then use the following checking procedures to check the fluid level. However, if there is a large leak, then it may be necessary to have the vehicle towed to a dealer service department and have it repaired before driving the vehicle further.

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.

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

How to Check Automatic Transmission Fluid

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.

Before checking the fluid level, prepare the vehicle as follows:

1. Start the engine and park the vehicle on a level surface. Keep the engine running.

2. Apply the parking brake and 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, move the shift lever back to P (Park).

4. Allow the engine to idle (500 800 rpm) for at least 1 minute. Slowly release the brake pedal.

5. Keep the engine running and press the Trip/Fuel button or trip odometer reset stem until TRANS TEMP (Transmission Temperature) displays on the Driver Information Center (DIC).

6. Using the TRANS TEMP reading, determine and perform the appropriate check procedure. If the TRANS TEMP reading is not within the required temperature ranges, allow the vehicle to cool, or operate the vehicle until the appropriate transmission fluid temperature is reached.

Cold Check Procedure

Use this procedure only as a reference to determine if the transmission has enough fluid to be operated safely until a hot check procedure can be made. The hot check procedure is the most accurate method to check the fluid level. Perform the hot check procedure at the first opportunity.

Use this cold check procedure to check fluid level when the transmission temperature is between 27C and 32C (80F and 90F).

GMS Sierra: Automatic Transmission Fluid (6-Speed Transmission). 1. Locate the transmission dipstick at the rear of the engine compartment, on the passenger side of the vehicle.

1. Locate the transmission dipstick 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.

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

3. Install the dipstick by pushing it back in all the way; wait three seconds, and then pull it back out again.

4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the reading.

GMS Sierra: Automatic Transmission Fluid (6-Speed Transmission). 5. If the fluid level is below the COLD check band, add only enough fluid as necessary to bring the level into the COLD band. It does not take much fluid, generally less than 0.5 Liter (1 Pint). Do not overfill.

5. If the fluid level is below the COLD check band, add only enough fluid as necessary to bring the level into the COLD band. It does not take much fluid, generally less than 0.5 Liter (1 Pint). Do not overfill.

6. Perform a hot check at the first opportunity after the transmission reaches a normal operating temperature between 71C to 93C (160F to 200F).

7. 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.

Hot Check Procedure

Use this procedure to check the transmission fluid level when the transmission fluid temperature is between 71C and 93C (160F and 200F).

The hot check is the most accurate method to check the fluid level. The hot check should be performed at the first opportunity in order to verify the cold check. The fluid level rises as fluid temperature increases, so it is important to ensure the transmission temperature is within range.

GMS Sierra: Automatic Transmission Fluid (6-Speed Transmission). 1. Locate the transmission dipstick at the rear of the engine compartment, on the passenger side of the vehicle.

1. Locate the transmission dipstick 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.

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

3. Install the dipstick by pushing it back in all the way; wait three seconds, and then pull it back out again.

4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the reading.

GMS Sierra: Automatic Transmission Fluid (6-Speed Transmission). 5. Safe operating level is within the HOT cross hatch band on the dipstick. If the fluid level is not within the HOT band, and the transmission temperature is between 71C and 93C (160F and 200F), add or drain fluid as necessary to bring the level into the HOT band. If the fluid level is low, add only enough fluid to bring the level into the HOT band. It does not take much fluid, generally less than 0.5 L (1 pint). Do not overfill.

5. Safe operating level is within the HOT cross hatch band on the dipstick. If the fluid level is not within the HOT band, and the transmission temperature is between 71C and 93C (160F and 200F), add or drain fluid as necessary to bring the level into the HOT band. If the fluid level is low, add only enough fluid to bring the level into the HOT band. It does not take much fluid, generally less than 0.5 L (1 pint). Do not overfill.

6. 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.


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