Saab Problems? Ask a Mechanic for Answers ASAP
To have every forward gear as normal and no reverse, it is most likely to be a sprag (one way clutch) which is now a two way, as a failure.
I have seen many sprags become two way, or lock up.
It is always a transmission rebuild when this happens.
I would contact an auto transmission shop in your area for a quote, but as rough guess it could be between $4-6K depending on necessary parts.
Or possibly like this:
Has this just happened today?
I hope my advice has been of assistance to you.
How did you go with your problem?