I have a 1990 MB 300E that I bought in March of this year. The main problem that I have is with reverse. It will not engage unless it was allowed to cool for a very long time (like first thing in the morning), or if I am on a decline and the car rolls via gravity and may engage into reverse before it reaches the end of the decent. I can also feel it try to engage while in reverse, on level ground, and while revving engine. Is this car a candidate for a transmission transplant? Or is it something simple?