Well, it could be one or the other. Considering the mileage, the TC is definitely in need of replacing. However, to pinpoint the problem with the least amount of effort, I would suggest replacing the VB first and see if they helps. It's easier than pulling the tranny to replace the TC (although that must be done eventually).
Phoenix Hard Parts Rebuilt VB:
http://www.phoenixhardparts.com/index.asp?PageAction=VIEWPROD&ProdID=414 
