GM Service Manual Online
For 1990-2009 cars only

Automatic Transmission Operation Six Speed Transmission


Object Number: 1608885  Size: A3

The automatic transmission has a shift lever located on the console between the seats.

P (Park): This position locks the front wheels. It is the best position to use when you start the engine because the vehicle cannot move easily.

Caution: It is dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll.

Do not leave the vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when you are on fairly level ground, always set the parking brake and move the shift lever to P (Park). See Shifting Into Park . If you are pulling a trailer, see Towing a Trailer .

Make sure the shift lever is fully in P (Park) before starting the engine. The vehicle has an automatic transmission shift lock control system. You must fully apply the brake pedal then press the shift lever button before you can shift from P (Park) while the ignition key is in ON/RUN. If you cannot shift out of P (Park), ease pressure on the shift lever and push the shift lever all the way into P (Park) as you maintain brake application. Then move the shift lever into another gear. See Shifting Out of Park.

R (Reverse): Use this gear to back up.

Notice: Shifting to R (Reverse) while the vehicle is moving forward could damage the transmission. The repairs would not be covered by the vehicle warranty. Shift to R (Reverse) only after the vehicle is stopped.

To rock the vehicle back and forth to get out of snow, ice, or sand without damaging the transmission, see If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow.

N (Neutral): In this position, the engine does not connect with the wheels. To restart the engine when the vehicle is already moving, use N (Neutral) only. Also, use N (Neutral) when the vehicle is being towed.

Caution: Shifting into a drive gear while the engine is running at high speed is dangerous. Unless your foot is firmly on the brake pedal, the vehicle could move very rapidly. You could lose control and hit people or objects. Do not shift into a drive gear while the engine is running at high speed.

Notice: Shifting out of P (Park) or N (Neutral) with the engine running at high speed may damage the transmission. The repairs would not be covered by the vehicle warranty. Be sure the engine is not running at high speed when shifting the vehicle.

D (Drive): This position is for normal driving. It provides the best fuel economy. If you need more power for passing, and you are:

    • Going less than 35 mph (56 km/h), push the accelerator pedal about halfway down.
    • Going about 35 mph (56 km/h) or more, push the accelerator all the way down.
M (Manual Mode): This position, allows you to change gears similar to a manual transmission. If the vehicle has this feature, see Driver Shift Control (DSC).

Driver Shift Control (DSC)

To use this feature, do the following:

  1. Move the shift lever from D (Drive) rearward to M (Manual).
  2. While driving in manual mode, the transmission will remain in the driver selected gear. When coming to a stop in the manual position, the vehicle will automatically shift into 1 (First) gear.


    Object Number: 1696956  Size: B3
  3. Press the + (plus) paddle located on top of the steering wheel controls forward to upshift, or push the backside of the shift paddle rearward to downshift.

The Driver Information Center (DIC) in the instrument cluster will change from the currently displayed message to the letter "M", For Manual position, and a number indicating the requested gear range when moving the shift lever forward or rearward.

While using the DSC feature the transmission will have firmer shifting and sportier performance. You can use this for sport driving or when climbing hills to stay in gear longer or to downshift for more power or engine braking.

The transmission will only allow you to shift into gears appropriate for the vehicle speed and engine revolutions per minute (RPM):

    •  The transmission will not automatically shift to the next higher gear if the vehicle speed or engine RPM is too low.
    • The transmission will not allow shifting to the next lower gear if the vehicle speed or engine RPM is too high.

Second or Third Gear Start Feature

When accelerating the vehicle from a stop in snowy and icy conditions, you may want to shift the gear select tap switch into Second or Third gear. A higher gear allows you to gain more traction on slippery surfaces.

With the DSC feature, the vehicle can be set to pull away in Second or Third gear.

  1. Move the shift lever from D (Drive) into the M (Manual Mode).
  2. With the vehicle stopped, press (+) end of the button to select Second or Third gear. The vehicle will start from a stop position in Second or Third gear.
  3. Once moving select the desired drive gear.

The shift lever is located on the console between the seats.


Object Number: 1509574  Size: A2

There are several different positions for the automatic transmission.

P (Park): This position locks the front wheels. It is the best position to use when you start the engine because the vehicle cannot move easily.

Caution: It is dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll.

Do not leave the vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when you are on fairly level ground, always set the parking brake and move the shift lever to P (Park). See Shifting Into Park .

Make sure the shift lever is fully in P (Park) before starting the engine. The vehicle has an automatic transmission shift lock control system. Fully apply the brake pedal, and then press the shift lever button before shifting from P (Park) when the ignition key is in ON/RUN. If you cannot shift out of P (Park), ease pressure on the shift lever and push the shift lever all the way into P (Park) while maintaining brake application. Then press the shift lever button and move the shift lever into another gear. See Shifting Out of Park .

R (Reverse): Use this gear to back up.

Notice: Shifting to R (Reverse) while the vehicle is moving forward could damage the transmission. The repairs would not be covered by the vehicle warranty. Shift to R (Reverse) only after the vehicle is stopped.

To rock the vehicle back and forth to get out of snow, ice or sand without damaging the transmission, see If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow .

N (Neutral):  In this position, the engine does not connect with the wheels. To restart the engine when the vehicles is already moving, use N (Neutral) only. Also, use N (Neutral) when the vehicle is being towed.

Caution: Shifting into a drive gear while the engine is running at high speed is dangerous. Unless your foot is firmly on the brake pedal, the vehicle could move very rapidly. You could lose control and hit people or objects. Do not shift into a drive gear while the engine is running at high speed.

Notice: Shifting out of P (Park) or N (Neutral) with the engine running at high speed may damage the transmission. The repairs would not be covered by the vehicle warranty. Be sure the engine is not running at high speed when shifting the vehicle.

D (Drive): This position is for normal driving with the automatic transmission. It provides the best fuel economy. If you need more power for passing, and you are:

    • Going less than about 35 mph (55 km/h), push the accelerator pedal about halfway down.
    • Going above 35 mph (55 km/h), push the accelerator all the way down.

Downshifting the transmission in slippery road conditions could result in skidding, see "Skidding" under Loss of Control .

I (Intermediate): This position is also used for normal driving. However, it reduces vehicle speed without using the brakes for slight downgrades. If constant upshifting or downshifting occurs while driving up steep hills, this position can be used to prevent repetitive shifts. You might choose I (Intermediate) instead of D (Drive) when driving on hilly, winding roads, so that there is less shifting between gears. The engine will not Auto Stop when the shifter is in I (Intermediate). See Starting the Engine

L (Low): This position reduces vehicle speed more than I (Intermediate) without actually using the brakes. Use it on very steep hills, or in deep snow or mud. If the shift lever is put in L (Low), the transmission will not shift into L (Low) until the vehicle is going slowly enough.

Notice: Spinning the tires or holding the vehicle in one place on a hill using only the accelerator pedal may damage the transmission. The repair will not be covered by the vehicle warranty. If you are stuck, do not spin the tires. When stopping on a hill, use the brakes to hold the vehicle in place.