87 Grand National hot trans problem

This has been a bit of a stumper. I'm the original owner of an 87 GN which now has 23K miles on it. After the car get good and warmed up in warm weather the trans acts as if it's trying to go quickly into 4th gear. When it gets this way it also seems to be staying in high gear when slowing to a stop or for a corner. I've driven the car with a diagnostic tool hooked up, and the lock-up converter looks to be working properly. To take that out of the loop I have tried unplugging it, but the problem still persists. Trans fluid looks good, pan is pretty clean, and the car hasn't been raced. The problem was very intermittant initially, a few years ago, but now is happenening almost every time it gets hot. Turning off the ignition and re-starting helps briefly. Anybody else seen this?

Try adjusting the TV cable. After you get done adjusting it, move it one click back towards the firewall. If you need directions on how to adjust it, just post up and let us know.

Andy

Everyone seems to have a different idea how to adjust the thing- I've been told hold the clamp in, then move the throttle fully, then release. Is this manner correct?
Vic

push the little button thing, and move the cable all the way back towards the firewall. Let go of the button, then give it full throttle. then very carefully move the cable one click back towards the fire wall.

Thanks, I'll give that a try and let you know what happens!
Vic

Thanks, I'll give that a try and let you know what happens!
Vic
FYI Everyone- As I suspected it's not a cable adjustment problem. When the 200 trans heats up, there is a mechanical valve that can stick and cause the trans to shift erratically, mostly that it goes quickly into high gear (4th) and want to stay there. A shop in my area knew of the problem, cleaned and polished the valve and also re-gasketed the valve body. Seems to be the cure, and doesn't require removing the trans from the car.