Over the last couple of days my auto box is intermittently not changing down for about 15secs at 2500rpm. Under normal driving it usually changes down at about 2000 rpm. It's a journey I do daily so it is not the road or the way I am driving. It is almost like it is going into sports mode all on it's own. Has anyone else experienced anything similar? I've only had the auto for a couple of months so I haven't a huge amount of experience with auto boxes.

I suppose you mean "changing up", not down.

Yes, I've seen such a behavior at an autobox when there is an increased forward resistance.
For example strong, frontal and in opposite direction winds.

Labradorslave wrote:

Over the last couple of days my auto box is intermittently not changing down for about 15secs at 2500rpm. Under normal driving it usually changes down at about 2000 rpm. It's a journey I do daily so it is not the road or the way I am driving. It is almost like it is going into sports mode all on it's own. Has anyone else experienced anything similar? I've only had the auto for a couple of months so I haven't a huge amount of experience with auto boxes.

That may explain it Alex-we have had strong winds the last couple of days. I did also wonder if the temperature was a factor-it has been warm up until the last few days. Apologies for getting my up/down back to front-long day at work!

The autobox retards a little the gear changes only when the gearbox oil is cold. But not so much.
Load is the main factor for a variable point gear changes. And a strong frontal wind combined with the "brick" type aerodynamic form of our cars, is translated in an increased load for the engine. Just like when you tow something.