Gear Box Sporadically won't Disengage from 3rd Gear Topic is solved

[GG]

I have a 1991 Volvo 740 Turbo. Last summer, whenever I started up my car after it had been parked in the sun on a hot day, the "orange up arrow" would stay lit on the dash indicator light panel which showed that my transmission was locked in 3rd gear. When driving under this condition, the light would sometimes go off then the car was able to shift into overdrive. Sometimes it would not go off and the engine would never disengage from 3rd gear. Pushing the button on the side of the automatic gear shift would not disengage the 3rd gear. I used to only use this feature when I was driving down the Alps (I live in Germany and work for the U.S. Army). Unfortunately, the 3rd gear lock is occurring more often, and sometimes it comes on while on the autobahn and drops me into 3rd gear and jumps the RPMs up the scale. I had taken it in to the Volvo dealer for some other work and asked them to check into this problem. Something may have got lost in the translation, so I'm still suffering from the problem. Can you tell me what parts or work I may need to have done on my car? I had regular Volvo maintenance and parts and the car runs very well with 171,000 miles on it.