I bought my 2006 Scion xB (automatic) about 4 months ago. At the time of purchase I was instructed by my salesman to drive with the Over Drive switch (located on the gear shift) turned off at all times.

Does anyone have an opinion on this? What does that switch actually do?

Thanks,
Malan D

Not sure why they would recommend that. I do almost all freeway so my OD is on all the time. The only time I turn it off is when I'm getting on the freeway and don't want to stomp on it. When I'm up to around 60 I turn it off and OD kicks in. Usually drops the RPMs over 1000.

The higher the RPMs the more wear and tear and less gas milage.

From Wikipedia:

"Generally speaking, overdrive (OD) is the highest gear in the transmission. Most automatic transmissions have 3 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 30 - 40 mph (50 - 65 kph) depending on the load). When it is off, the transmission shifting is limited to the lower gears. For normal driving conditions, operation of the overdrive should be enabled.

"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 3rd 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 3rd gear, shifting back and forth. In this case, switching it off can help the transmission to 'decide'. It may also be advantageous to switch it off if engine braking is desired, for example, driving downhill."

quick question
how do i know if O/D is on because when i press the button O/D off comes up on the little screen on the car were the time is

When the off sign is not lit up then the OD mode is on.

so what do you recomend i do mostly city driving

keep it on. i have no idea why he would tell you to keep it off, unless you live in an area with a lot of incline changes.