why not go to a transmission shop and get them to give you an estimate for a fix for this and see what they say....
i changed out motor mounts on my 93 taurus and broke the wires from the VSS(vehicle speed sensor) and it kept the transmission in first gear... had to drive 5 -10 mph all the way home.. thought for sure it was the trans. going out.. it was the wires to the VSS that told the trans. to stay in first gear..... might be something as simple as this, keep fingers crossed....
