Mercedes Benz repair: 1984 300D Turbo Wont leave park, lock smith, 84s

Question
Ok, I've been trying all kinds of sites, but hoping you can help me. I recently bought a 1984 MB 300D Turbo, and after a couple of days, I couldn't go from park to reverse. It locks up right before it should slide into reverse. I've had a few people tell me it may be transmission trouble, but there's a push lock on the drivers side of the console about half way to floorboard. I can't find out what this lock does, but I pushed it in all the way when I was looking for what popped the hood. I'm hoping this is the issue, but was hoping for some confirmation before I called a lock smith.

Thanks in advance

Answer
Good morning!What you want to do is take the linkage loose under the car and see if it is the linkage or transmission. WHen you get this loose then you can determine what you may need to do. If the car has a park lock cable, Then it is more than likely the problem. You can tell by looking on your console and see if it says to push brake before taking out of gear. I didnt think the 84s had this feature. But it well may have!
If it does , the cable goes from the shifter to the brake petal.
Thanks and i hope this helps. Rick