I've read occasionally about an issue with the C4 transmission Park gear liking to 'slip' easily out of position and go into reverse. Mine started doing that. A few months back I came across a post in the archive talking about how to remedy it by replacing something in the transmission but, go figure, can't locate it now. Anyone have info about how to do this/what to get/know the thread? Much appreciated!
It may just be an adjustment issue or it could be the parking pawl in the transmission is worn, if you do a search under parking pawl you may find your answer
Thanks for the input. I took the linkage off and tested the column shift and it's mechanisms seem to be working fine. The lever on the transmission is easy to 'flick' down from park to reverse; for example, a no-effort push with the index finger will put the lever into reverse position but then I have to use both fingers to get the lever to move into any more gear positions. I don't know if it's supposed to be like that. Is it? I could see where that makes sense if the column is holding it in 'lock' position.
Did you try moving the shifter arm on the transmission with linkage from column unhooked, if you did and this was the results then it sounds like the parking pawl in the transmission is bad you should have to use a good amount of effort to get it out of park. Time to drop the pan and have a look
There is a assist spring on the linkage inside the trans that's always trying to push the trans out of park... Misadjustment, loose bushings, coupled with engine vibration will flip trans into reverse and car backs into something all by it's self... Also possible to go round & around in a circle... Years ago on 60 Minutes, there was a video clip of a MK-III Lincoln doing just that... Yes Lincolns used C6 trans, all Ford auto trans from the '60s, through the '70s have the trait built in...
Thanks! I'll put the pan removal on my list of things to do and see what's going on. I didn't leave the linkage on the transmission when i tried my switch test, it was removed. I remember seeing a video awhile back of a Lincoln, I think, that was in a parking lot going in circles in reverse and a guy in the center timing it to jump in and stop it. He did.