Whats up with the O/D on/off button on the auto? I do a decent amount of city driving which will get me above 40 mph (where mine kicks into O/D) but shortly thereafter I am downshifting. Is this to keep wear off of O/D or clutch? Anything to be worried about? My roomate (an engineer for Toyota) says it's worthless, but a mechanic friend says it's worth keeping it out of O/D. Any thoughts?

 

Depends on how your driving style is if your speed mostly below 50 (stop and go city driving). I'd say keep OD off for better reaction.
Otherwise, just leave it on all time. It WON'T harm the engine or gear at all. There are still many Corolla without OD running 4000+rpm at 70mph and work fine.

 

keeping it out of overdrive gets it to the next gear quicker, and should save gas mileage. i use it around town up to 40 then take it out, a little more pep. Feels like its winding out a little much once you get into the 60 range.

 

I am not concerned about over-revving, what I was concerned about was going in and out of O/D many times from stoplight to stoplight.

 

how far is stop light to stop light??

under 40mph o/d off would be better in a city driving

 

so city off..and express on?

 

OK, I see what's your concern and the answer is " no problem " at all. you can turn it on/off as many time as you want. It wont harm the mechanisum.

 

will it affect my wifes milage

 

Fairly long, perhaps a mile where going 55 is good. I estimate I get into and come out of O/D 8 times en route to work, 8 coming back.

Secondary question: why is it included? When I put my foot down in O/D, it downshifts on its own, and I certainly am not towing anything.

 

n00bs

 

Not quite, just never owned a vehicle with this feature (without downshifting) and I was gathering others thoughts.

 

The OD is suppose to give one better gas mileage. I turn it off when going into the mountains.