over drive & hold button para saan?

[v6dreamer]

Generally speaking, overdrive (OD) is the highest gear in the transmission. Most automatic transmissions have three speeds and overdrive (fourth speed). Overdrive allows the engine to operate at a lower rpm for a given road speed. This allows the vehicle to realize better fuel efficiency, and often quieter operation on the highway. When you switch it on, you allow the transmission to shift into overdrive mode after the certain speed is reached (usually 70+ km/h, 45+ mph) depending on the load). When it is off, the transmission shifting is limited to the lower gears. For normal, operation of the overdrive should be enabled only if the average speed is above 70 km/h (approx. 43 MPH). It may be necessary to switch it off if the vehicle is being operated in a mountainous area.

The automatic transmission automatically shifts from OD to third gear when more load is present. When less load is present, it shifts back to OD. Under certain conditions, e.g.: driving uphill or towing a trailer, the transmission may "hunt" between OD and the third gear, shifting back and forth. In this case, switching it off can help the transmission to 'decide' para hindi shift ng shift ang tranny mo. It may also be advantageous to switch it off if engine is desired, for example, driving downhill para pigil ang takbo. Your vehicle's owner's manual has information and procedures regarding such situations.

* attyallanlatras
If your car equipped w/ OD it should have a marked OD on the gearshift or either a OD button on the shiftknob. Some other car's w/ OD equipped like this D, d3, 2, 1.....so the D is the OD. If you see one of this in your car then you have OD.