I am beginning to notice a whine from my transmission. It will appear for a few days (or hours) and then go away. It's a mid range tone and occurs only under load ( goes away when going down hill ) It is not from the read end. It does not seems to vary in intensity or volume with speed. I changed the filter pan and fluid last winter. The transmission shifts up and down almost imperceptibly even when being driven "in a spirited manner" and in sport or regular mode and when using the J gate. Occasionally the shift down from second to low will be a bit clunky when coming to a low speed stop but all upshifts are great. Sometimes when it whines...if I shift into neutral going down hill , the whine will not come back when the car is under load again. It does not seem to be affected by whether the car is hot or cold. The whine does not seem to change performance in any way I can notice. There is no sign of any leaks.

I have only owned a few cars with automatics so I'm hoping someone with some experience might be able to suggest what "might" be going on

 

Barry,
I had something that sounds very similar to yours on my 97 XK8.... changing the filter and adding the correct amount of trans fluid made it disappear and has never come back.
Mike in TN

 

Changed the filter and fluid 6 months ago.