2010 Buick LaCrosse Owner's Manual - Page 250

8-30 Driving and Operating 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 lower gear if the engine RPM is too high, nor to the next higher gear when the maximum engine RPM is reached. While in the DSC mode, the transmission will automatically downshift when the vehicle comes to a stop. This will allow for more power during take-off. When accelerating the vehicle from a stop in snowy and icy conditions, you may want to shift into second gear. A higher gear allows you to gain more traction on slippery surfaces. Drive Systems All-Wheel Drive With this feature, engine power is always sent to all four wheels. It is fully automatic, and adjusts itself as needed for road conditions. When using a compact spare tire on an AWD vehicle, the system automatically detects the compact spare and disables AWD. To restore AWD operation and prevent excessive wear on system, replace the compact spare with a full-size tire as soon as possible. See Compact Spare Tire on page 9‑76 for more information. Uplevel Display Shown, Base Model Similar The display on the instrument panel cluster will show which gear the vehicle is in. The number indicates the requested gear range when moving the shift lever forward or rearward.