I have an early 60s powerglide transmission that locks in park, works in reverse, but when I put it in neutral, drive, or low, it stays in reverse? I even attempted to remove the shifting linkage and do it by hand with the car raised and it still does the same.
obviously I am thinking it is internal, but what exactly internal could it be? If anyone has any expertise in this area I would appreciate the help. Hopefully I can do this fix “in vehicle”.

 

Is park, and reverse next to each other? I had a 57 Bel Air that reverse was all the way down. If it is only going park, or reverse, pull the pan, and check the internal linkage. Is the shifter actually moving into drive?