I have a 91 300SL with about 110,000 miles automatic trans...my wife was pulling into a parking space and when she backed up to straighten our the car a little...the car would not shift into gear..it's been driving fine up till then...no laboring in gears, no leaks or noise, didn't hear any clunks...the car will hold in park but does not shift into any gears..? Any ideas would as always be appreciated.

Thank you