First, confirm that the exterior shift linkage is all connected and moving. If so, then there is a "rooster comb" on the valve body that connects the shift linkage to the manual valve and park rod. This "rooster comb" is pressed onto a the shaft that connects to the shift lever and they do break loose on occasion giving the exact problem you are having. You'll have to drop the pan to confirm, but it is a relatively inexpensive fix. You can either replace the comb/shaft or if you can get it back in the correct position, it could be tack welded back together.

Here's a picture.