90 deville shifter problems

I think this car has had a linkage problem. Suddenly it won't shift nito the park position and the key won't come out. Also, when putting it in Drive, the shifter had to be placed in the d3 position for it to run through all gears, otherwise it's in one of the low gears all the time. When in d3 it runs fine, but the linkage seems messed up. I'm hoping this is a bushing or other lightweight problem. Any info on how to go about it is appreciated.

Thanks