'95 GT Transmission Problem

I have a 1995 GT that is having a problem shifting. At approximately 45 mph the engine races for one to three seconds, then it will shift HARD.
Right now this is the worst problem, but it doesn't seem to be the only problem. In general, the car just doesn't seem to know what gear it needs to be in, or when it needs to shift.
I have had a lot of transmission issues with this car. I used to take the car to the dealer and just have them take care of it...but
1) the car isn't under warranty any longer and
2) they have never really taken care of it.
I can find two reciepts from the dealer (3/2001 and 10/1998) where it seems a similar problem was reported.
The car hasn't been driven much in the last 3.5 years, so I have forgotten much of my earlier frustration.
Has anyone else experienced similar issues? Is it a matter of loading a new computer program? Maybe just a bum transmission? Can I go back on Ford for not fixing the problem the first (or second, or third) time when it was under warranty? Take the car to a transmission shop as opposed to the dealer?
Any input would be appreciated.

I'd take it to a reputable tranny shop. In my opinion, most Ford shops are just crap. I had my 3650 rebuilt and the morons failed to check the pressure plate or flywheel to see that hot spots were abound... and the shifter cable took a crapper.

$1000 bucks later, the car runs with another crap shifter cable.

I am having a simular problem with my 92 GT!!!
when it gets up to temp. it jerks and kicks real bad!! Almost as if it was going to stall, but working the clutch I can control it a little. Not alowing me to up to speeds past 30mph... Any advise would be great..

check your fluid, could also be a problem with the electronics in it