Mystery sqeal in my 940???

[pitshack]

Hey there everyone. This is my first post on this forum, although I have lurked and used it numerous times to diagnose my car, anyhow. I own a 1995 volvo 940 with a 2.3, it's about to turn 200k.
It has recently developed this mystery squeal, that is the best word I can use to describe it. It sort of sounds like a belt but it is definetely not. Hopefully a little background as to when this squeal stated will aid someone in helping me figure out what is going on.
My girlfriend came home and told me the car wasnt running right. It turns out the car was randomly dropping out of overdrive and into third gear on the highway doing about seventy mph. At the same time my girlfriend said the squealing started.
I have no idea how hard she was pushing it on the highway when it was dropping into third gear but I cant help but think the tranny may have been damaged. The sqeal seams to be coming from the general are of the rear of the engine compartment on the passenger side.
The squeal has a certain rythmic quality to it that increases as you give it gas then stops, then starts again. It also tends to be loudest when the car is cold, then goes away as the car warms up. I cant find any rubbing that could be causing the aqueal.
This car only has to last until July when we will be able to afford a new car so I'm hoping some one can help me out.