Shifting (A/T)

[eTiMaGo]

The way I understand it...

Manual shifting of an auto transmission is not a problem in theory. In fact, it should not cause any problems, most of the basic "sequential" boxes are just that, automatics with gear change overrides. (BMW's SMG and fancier sequentials are basically an automated manual gearbox, but I digress).

As with any other mechanical component, if you use it within its normal parameters, there should be no problem shifting an A/T. But, just like with anything else, problems arise when you abuse these normal operation parmeters. Auto transmissions are inherently less robust than manuals, coming in to a corner at speed and using ONLY the gearbox's downshift to slow yourself down is probably not a good idea.

Just like the manual Razr posted up above mentions, the main problem is overheating of the transmission.

So, the Cliff's Notes: A/T shifting? Not too much to worry about as long as you don't thrash the thing or force it to run in low gears excessively. Just like anything "fun" you can do with your car, there's the chance of it reducing the overall life of the vehicle.