Greetings from over the Pond.
English is not my first Language so i apologize for any misspelling or bad Grammar.

I got myself a 1985 Z28 700r4 a while back and did not get around to bring it back on the road.
I'm just starting to work on it again.
My Problem is the following:
When in idle, Shifter on P the car rolls back (litteraly just pushed open my Garage Door).
Shifter on N the car moves Forward.
When i turn of the engine and put her in P again, i can push the car in any direction (which should also not happen).

Is this a known peoblem?
I really hope i dont need to take out the Transmisson.
Thanks in Advance for replys.

 

shift cable outer part has probably came unclipped off the shifter frame- my car did this-little plastic part broke and i had to make a clamp to hold the cable to the shift handle mechanism frame

 

The car will roll in N.

It should not roll at all in P. Rock a bit but not roll.
Cable could need adjustment, it could be popped out of its mount or the parking pawl could be broke in the trans.

 

Perhaps the "paw", If there is one in the 700 4r like in the th350 & th400, has broken, then the car will move while in park. Do all the gears work otherwise?

 

The shifter linkage cable was not adjusted correctly.
When i selcted "P" on the shifter the selector on the transmission where the cable is attached to was between "P" and "R" which means when i shift to "N" its between "N" and "D".
Thats why it wanted out the door so badly.

Someone hleped me out with scans from a repair manual so it was pretty straight forward:

1. losen cable on transmission
2. put shifter in "N"-position
3. put selector? on the left side of transmission into "N" Position
4. reattach cable aand it works.
5. fix Garage door

 

I have done this on a th350 a few times. U remove the tranny cable from the selector on the side of the trans. Place the selector into the "park" position, then move two clicks to neutral. Move shifter to "N' position. Adjust the trans cable appropriately & reconnect to selector. Start engine & test drive. U may end up readjusting the cable to get it right. Worked from me.

 

When you say Adjust, what do you Adjust? There is only one hole for the shifter linkage. Where is the adjusting done at? Also, how does the cable go out of adjustment on it's own? Thanks

 

It has been about 7 years since I installed a new shifter cable in my 1972 Buicks GS which I sold in 2021. If I still had the car I would crawl under it & refresh my knowledge on the adjustment procedure. I made no change at the shifter itself. I will keep trying to find the whole procedure.