Really simple questions here. I know NOTHING about autos and CBA to learn about them to find out some simple questions

When you put your foot down in an auto. Does the gear always change up at the same RPM regardless of throttle postion and load? Or does the change up point (RPM) change depending upon the throttle postion/load? In example, it'll change up at 4500RPM regardless of whether you're thrashing the shit outta it or cruising? Or does it vary the change point as I thought earlier? I'd hae thought it would be varying as people do thrash autos as well as cruise in them.

Also, what exactly is a stall converter with the RPM tag assigned to it mean? Ie, one of these. http://www.jegs.com/webapp/wcs/store...10002_70456_-1 What does it do also?

Finally, on an automatic gear gate in the car. I understand what the P, R, N and D mean. But when it says 1,2,3 etc. Does it mean you can hold it in 1, lift off, then bang it up in to 2 then put your foot back donw like a manual? Or if you leave it in 1 will it just sit there revving it's tits off? Likewise for 2, will it drop to 1 or just stay in 2 till the redline? Then once at the redline, what'll happen? Change up or keep revving to the limiter.

Sorry for all the questions, I'm a bit bored and curious and my mate who knows autos isn't around.