Auto trans shifting

[Tonveranga]

Is it safe to shift from D to 3rd (under 60mph) on auto trans? For passing and more aggressive driving i guess...

[anarchy1024]

Generally speaking, yes, for modern automatic cars. The computer in the car knows if downshifting would cause the engine to rev too high, and doesn't do it in that instance.
It won't, however, upshift beyond third, even if you're redlining the engine, so you'll want to watch your tachometer (engine rev meter) when accelerating while manually keeping the gear low. Keep in mind that driving with the engine at higher revs puts more stress on it, increases wear, increases fuel consumption, etc.

Manually downshifting is also useful for increasing the engine braking effect, when going downhill or driving with heavy loads.

Your owner's manual should say the speed ranges that each gear can handle (at least, it does in the 5MT manual).

[hocrest]

It's not really going to hurt it, but like Anarchy mentioned it does cause extra stress on most moving parts.

I don't really think it is necessary though. Subaru auto's are fairly good at dropping a gear when you get aggressive with the gas pedal. Once you get the feel for it, you can use the gas pedal to give Oldsmobile like smooth acceleration or redline shifts into 2nd, 3rd and 4th while never taking it out of "D"

[anarchy1024]

That's true. The only time I felt it might be necessary to manually downshift is when coasting downhill with a heavy load, and I want to use engine braking instead of riding the service brakes. The auto trans usually uses the highest gear unless forced into something lower.

[Tonveranga]

Thanks for all the replies! i guess i'll just punch the gas when necessary!