Oldsmobile/Buick: car will not go into reverse, mileage transmission, high mileage

Question
we have a 95 oldsmobile cierra sl.  The car will not stay in reverse.  It goes into all the other gears but is going back into park after a few seconds.  We need some help? The car has 185,000 miles is in good shape and has very few maintenance problems. We have been told the reverse is blocked but the dealership is not saying what is doing this and how it can be repaired.  

Answer
Hi DeQuincey,
There are several transmission components that may be the culprit, either electronic or parts. On the worse end, if the dealership is saying reverse is blocked at the transmission, the only cure is a rebuild. Most shops, including the dealership will not attempt repairing a high mileage transmission, because the can't gaurantee the work. It is not uncommon for electronic trannies to loose a gear when a car reaches high mileage like yours. Some internal parts are made of a nylon type plastic. So you can see how wear can effect. Not like the good ole days of the turbo 350 and 400 transmissions.  Here's what I would do. Rescue the car from the dealership and find a good independent and reputable shop that does nothing but this type of work. Cost wise you will save money, and the job will be done right. With a 185,000mi, the inevitable has occured. Consider your car to be a good one, most of todays don't make it that far. A rebuild is going to be expensive because of the complexity. Your looking at roughly $800-$1,200 for rebuild and installation. I've seen dealership's go as high as $2,000. Hope this helps! Ray