New to the forum. Plus I just purchased a 1987 6.9 diesel. Runs well enough and is in decent shape. She just needs some love. As i get an idea for her quirks and how she runs I have found that she doesn't always want to stay in park and actually the automatic shifter in general is shotty. The the gear indicator in the dash is broken which isn't the big deal. But when parking on an incline it tends to want to pop out of park. As a whole the parking gear doesn't want stay. Because when I go to start it I have to slam the shifter up into parking until it catches so I can start the engine. I am not a car guy but I can do a lot of basic stuff on normal gas engines. Just looking for some help because this is one of the many issues I would like to fix.

 

I would check the shifter linkage for a bad/missing bushing

 

it could very possibly also just be out of adjustment too.
i bought a 78 F250 with a "bad starter" for a parts truck. the trans linkage was out of adjustment and it would not start in park or neutral.
only would start in reverse or drive. but the kid did not know that. i winched it up on the trailer and took all of 30 seconds to figure out what was wrong with it when i got home. it was clean enough that i sold it for 10 times more than i paid for it instead and got another parts truck.

 

That didn't exactly answer ... Could be needs adjustment and there is a procedure for doing so. I've read you get it into park. Maybe you need to start by loosening the linkage bolt to slacken the line a slight bit. In park you hang a weight onto end of shift level. Then tighten slack out of cable. You can look that up... Its been a time since I did it.

 

Until you get this fixed, rather than slamming the shifter into Park, just start it in Neutral. You don't want to make the situation even worse.

 

87 does not have a cable. it has linkage. it really is a simple as chocking the wheels, loosening the linkage, putting the shifter in park, making sure the trans in in park, and tightening everything back up. takes all of about 10 minutes to do unless everything is rust seized.