If the pcs is acting up again or your trans is just worn to the point where the shifts become too lazy for the pcm's liking then it will throw code P1811 which is for max adapt shifts and when this is present the pcm commands max line pressure. If you shut the car off and start it back up and the noise goes away until the rough shifts start again then you may be looking at a bad pcs again or as mentioned above the trans is getting worn. The pcm monitors shift timing in milliseconds and if it falls outside of a given range then the code will set but will only be present often during the condition but should store in the pcm memory. When max line pressure is present you will hear a whining noise because the pump is working harder. To rule out a few things try this...... Put the shifter in drive when you hear this noise and if the noise is present with the car NOT moving then hold your left foot on the brake pedal and give the car some throttle to "load" the engine and work against the torque converter. Dont give it a lot of throttle just enough to rev the engine up to around 2K or so. Is the noise present sitting still in D or while revving it sitting still in D? The only thing that can make noise if the car is not moving and the shifter is in D or R for that matter is the pump or the torque converter itself. It should be safe to rule out the engine since you say it makes no noise in P or N range.
