The automatic transmission of my 2014 Mazda3 (2.5L) with 80K has recently started switching to a lower gear. At about 30mph it sporadically revs up the engine for a few sec (I think it goes from 4th to 3rd or from 3rd to 2nd), then it goes back. Then it can repeat the same trick in a minute or so.

Amazingly, I cannot reproduce it myself, but my son and wife do experience this regularly. I cannot say it's their weird driving habit: my wife has driven this car for years with no troubles.

I'd think the transmission fluid is low, but with Mazda lifetime ATF, the whole thing is sealed and there's no dipstick.

Anyone had this before? Is my transmission going to need to be replaced soon? Most importantly, is it safe to drive? I wouldn't want the downshift to occur at 80 mph.

 

*I recomend that you take it to a Transmissions service shop asap.

The "lifetime" fluid and/or service indicated by a few automakers so to say is more or less what the industry calls 100k miles. You are close.
Realistically on any vehicle I recomend to at least do regular service fluid and filter changes.


NO ONE has a crystal ball or clairvoyance that can answer your question about *continuing to drive it. I suppose one could ask the "EIGHT BALL" ?

 

FYI they do have a dipstick. Its very very short, bolted in-place & very hard to access.