Volvo Repair: 1992 Volvo 960 transmission problems, 1992 volvo 960, volvo 960

Question
I am considering buying a 1992 volvo 960 but the owner freely admits that it has transmissions problems.  The D3 gear work fine but the D4 gear slips sometimes.  I think that I would have to have the transmission reworked soon after I bought it.  Any thoughts on whether this is the best course of action and roughly (just to the nearest $100) how much this might cost?

Thanks for your help.  

Answer
Joe, dont buy it, not only does it have tranny issues but also bad cylinder heads on those early models.  There isnt a good tranny shop anywhere that I know that can fix those properly and to get a reman unit from Volvo would be around 2500 bucks.  hope this helped.  Roger