What's up, Audi World?

I have a '98 A8Q with a transmission problem. I just brought it to the shop today, but I would love to hear some opinions from you folks so I can be equipped when the mechanic calls.

Here is how it has gone from bad to worse... At 40-50 MPH and in 5th gear, the tranny acted like it wanted to switch gears. The RPM's would oscillate up and down. After a while, that was getting worse...but then, while going about 78 MPH, I would take foot off of gas and coast to slow down, and right around 68 MPH, the tranny would jump, but stay in 5th gear. Last week I noticed the jumpiness while mildly accelerating was getting even worse. Finally, we started to hear a whining sound while in park, neutral, and drive. I towed it to my mechanic who did some work on other things, but then he recommended a transmission specialist. I drove it there and was sick to my stomach because the whining got really bad and the tranny would jump while accelerating in 1st.

Do you think the pump is bad? Torque converter? I'm interested in your thoughts. Thanks in advance!