Over Drive Switch

[ae1awusn]

2005 Matrix, second owner, bought it in 2006 with 17,000, now up to 77,000...still runs fine, starts every time, gets 30 + MPG all the time.

The over drive switch on the shift, when can I use it, when should I NOT use it....what does it do (I see the RPMs pop up) .....is there any issues with switching it on & off, etc?

[circuitsmith]

Generally leave the overdrive on (lower RPM's).
The only situation you might turn it off is on hilly roads ~30-50MPH where the trans would otherwise frequently shift in and out of overdrive.

p.s. Change, don't flush the trans fluid every 30K miles.

[PA Firefighter]

It can also be used for merging onto highways from the on ramp, or for a little extra umph needed when passing. The reason the RPMs jump is because you're essentially shifting down to 3rd from 4th.

Oh, and when not to turn OD off? Rain or snow. It's like a Jake brake on a truck. You never would have it engaged during inclement weather.

Agreed on the tranny flush. Don't ever do it. Completely drain it and replace all gaskets and filters, then add new fluid. Or take it to AAMCO and they'll do it for you.

[blkavalon]

don,t flush ATF if you haven't changed it for a long time (really dark fluid). but its better to flush as a regular maintenance like every 25k. i do my flush every 25k on my avalon, currently have 172k miles. pull trailers/small boats all the time.