Automatic Transmission problems of the 1997 Buick Riviera

Goes out of high gear while driving between 35-65.

After stopping at an uncontrolled intersection, my front bumper was into the traffic lane so I backed up about two feet in case a car was coming from my left that I might not see. I shifted back into drive almost immediately so I could proceed across the lanes and complete my left turn. The transmission was slow to engage completely into drive and lurched for a few seconds before it let me accelerate into my left turn. I was almost broadsided on my right as this transmission needed a long pause before engaging from reverse to drive. I have had this transmission opened up and repaired by my Buick dealer twice in two years. Buick has published multiple service bulletins dealing with harsh shifting from reverse to drive and also harsh shifting in general. I took the car again into don snell Buick on Tuesday, November 2 and asked them to replace this faulty transmission or see if another service bulletin has been issued. After two days in which I had some normal 30000 mile serv ice done, the service foreman politely told me that this pause can't be fixed and I have to live with it. The problem only seems to be in the Riviera model not other Buicks. In this day of faster and faster computers, I find it hard to believe that this transmission must pause for a few seconds to engage in drive from reverse. How many accidents has this caused or will cause in the future? I guess since the Riviera is no longer made , this transmission issue will fade away in Buick's eyes. Hopefully you can nudge Buick into issuing a fix for this dangerous problem.