Hey,
Just curious abt the overdrive button on the auto xb shifter. I turned it off today and doing 60 on the highway my engine was workin harder and it was loud. I figured it couldnt be more efficient so i turned it back on. Any one know about what exactly it does and what having it on and off does for mpg?

Thanks,
John

 

O/D is your fuel saver. It should only be used for highway driving. I would recomend turning it off for city driving just because having it on puts more wear on the trans but thats just for city driving.

 

Turning your OD off helps with climbing hills, and gives you better "punch" when your driving around town.

 

O/D on allows the automatic transmission to shift into 4th gear. O/D off prevents the automatic transmission from shifting into 4th, making 3rd your highest gear. If you notice the automatic transmission shifting rapidly back and forth between 3rd and 4th (as it may on some hills), turn O/D off until you're off the hill. It'll save wear and tear on the tranny (and your sanity).

Unless you need a bit of engine braking or want to keep the AT from playing ping-pong with 3rd and 4th gears, keep O/D on.

The AT won't shift into 4th if the coolant is too cold (i.e., when the blue coolant light is on).

This *is* all in the owner's manual...

 

I use the button only rarely. It is just a convience of pushing a button rather than moving the shifter. I actually like the button more than moving the shifter. I only use it for climbing passes or I found I can get it to shift out of 3rd and back into high as I approach the top of the mountain pass by pushing the on/off switch which must trick the computer and will have it shift into high. I love that about the transmission.
Anything over 40 and I want it shifting into high so if I am going to be doing that for even a short bit I want it up in lockup.

 

Yeah, what the others said.

Turning O/D off will decrease your MPG quite a bit and will make your engine work harder. Also, at highway speeds (60-80MPH) the engine will be reving really high. Not very good for the engine.

I only switch it off when on hilly road (30-50MPH speeds) to stop the transmission grom "hunting" for a right gear.

If you need peppier car, buy a tC. :D

As far as engine braking goes, I've noticed that the car is quite smart. I was coming down a long hill (coasting at about 40MPH). Car was speeding up by itself. I then barely depressed the brake and held it on. Hill was steep enough so the car was still speeding up a bit. Then, it automatically downshifted which used the engine braking to slow down the car. I was impressed. Seems that the computer sensed that the brake was applied and the car was still speeding up, so it tried to assist the brakes by downshifting. BTW, all of this happened with the O/D still active.

Peteski

 

just think of your auto trany as a mountain bikes gears. when you have your bike in first gear you can peddle really fast but you dont go that fast, and if you start in the higher gears its really hard for it to start moving but once your moving along its realy easy to peddle and maintain that speed. and if your going fast and you switch gears into first remember how fast you have to peddle to maintain your current speed. the trany works the same way. use the OD its a life saver on your motor and trany. and yes click it off when you start climbing hills.