sorry to be the bearer of bad news, but my wife had the absolute exact experience as you recently in the Target parking lot nearby in our 96 855T. The planets are shot, and your trannie will fail if it hasn't since you wrote your orig posting.
I had a choice of a trannie from a wreck at Erie Vovo in NY for a few hundred bucks plus freight and a big bill for installation, or I found a superb trannie shop in lancaster, NY, (Wholesale Transmission) who I opted to have my own trannie pulled, and rebuilt. Job cost about $2K out the door with one year full warranty. It runs better than new. Now here is the important stuff--the Volvos have no trannie filter, so you should finish the job with Magnafine in-line filter from ipd. I will change the fluid after 12K probabaly.