accidently added power steering fluid to transmission
I would have the transmission fluid flushed or drained soon since you may need it anyways. If there's a filter in the transmission, choose a pan service where they remove the transmission pan, replace the filter and reinstall new fluid.
You don't mention make, model, or year, but in some makes, particularly in some year ranges, the two fluids are very different. Using ATF in the power steering of a Honda will destroy the seals, and using anything other than Honda ATF in the transmission will cause at least poor shifting. Power steering fluid is primarily a hydraulic oil, ATF is primarily a lubricant. I recommend you get the fluid changed soon.
It won't do it any good are we talking more than a half a liter? If it is a small amount you have no real serious problem. These systems are both hydraulic I use ATF in my power steering all the time. I have never done the opposite. I can say I would not freak out over a half a liter or less of oil. Any more than that get a full pan off filter changed tranny flush.
