1990 Acclaim odometer/speedometer

The odometer stopped working (analog) and I replaced it with a junk yard unit (entire speedometer) and a few months later that one stopped working as well. Replacing it with a rebuilt unit is expensive from what I seen so far on the internet. What would have to be done to replace it with a digital unit? Is there more to it than replacing the sending unit on the transmission and the speedometer? I would appreciate hearing from anyone who has actually done this or who knows where there is a technical bulletin that addresses the swap.