Shifting gremlins, hmmmm. No, on the whole, I would have to say that becuse I needed to think about that question for a minute, it must mean that the automatic has not drawn attention to itself. I just performed fluid and filter service on it over this last weekend and there were no surprises. One issue, however, that I did notice is that at high elevations, say, above 12000 feet, the shifting did seem to be a little more sluggish, possibly due to lower vacuum developed by the pump at high altitudes. I doubt this will be an issue with most folks. Aside from that, the transmission has been very well behaved. A note on Mark Herzig's comments: yes, Mark, I agree. This car definitely responds favorably to extended freeway driving. As this car is used almost exclusively for freeway trips over 30 miles, it always seems to be running at its best. Fuel mileage at about 85mph cruise is around 27 MPG.
Finally, a note on corrosion. Here in Colorado, we don't have huge problems with corrosion. More commonly, we have issues with UV damage. There can, however, occasionally be some salt on the roads in the winter time. I don't drive the car at those times, but if you do, one thing to watch out for is corrosion of the lower control arms in the rear suspension. One of the lower control arms in my car rusted in the area around the lower shock mount. Apparently, there can sometimes be small pinholes in the welds of the arm that can allow moisture to enter. The arms are apparently hollow. Once this moisture enters it slowly corrodes from the inside out (faster with salt, I imagine). This is difficult to detect and expensive to repair. The repair job for my car approached $1000. Keep an eye out for this when you evaluate a 300 SDL.