Truck Repair: removal of the shifter, floor shift, bottom right corner

Question
how do you remove a shifter from a 1985 chevy fullsize pickup truck

Answer
I assume you mean a standard tranny, with a floor shift?
There is a semi-dome shaped retainer where the lever comes out of the tranny. It has an oblong opening that the lever moves in.
Put a screwdriver...pretty good sized one, in the top left corner of that oblong opening.
Put another screwdriver in the bottom right corner of the opening. Probably need a helper to run one of them.
With the screwdrivers, push the cover down, and at the same time, counterclockwise.
There are some slots in the edge of that retainer, where you can't see them, that engage on some pins. Turning it like that will release it from the pins.

I have also done it with a pair of channel-locks, and even with my bare thumbs, but the screwdrivers are a little easier.

After it turns about an eighth of a turn, a spring will pop it up and out. Then pull the lever out.

Van