Joe C

i'm not sure the spring-loaded, pop-up function of the shifter button has anything to do with the key removal from the lock cylinder. anyone know for sure??? it just may be a different issue.still betting on a bad steering column, cylinder key lock assembly. BTW, ac delco OE replacements are still available, P/N D1453C (91 corvette w/ automatic transmission) - $38 + shipping -- rockauto. OP needs to get back to us with a status update....

65Z01

Since the shifter button is "up" in N, will the key come out in that position?
If so, can you than shift into P?

Joe C

I just went out to check the button/key relationship in my 85. w/ the shifter in park and the key in the run position -- if I push the button down and hold it, I can turn the key to off, but i can't remove the key. this is acting much like the OP's problem. i can't push the button down with the key in the off position either, so back to my earlier post, it appears that there is a relationship between the button and the key position. it still doesn't mean that the root cause of the problem is not the key lock cylinder. if i were the OP, i'd remove the button, shift ****, and console bezel, and inspect everything - maybe something is misaligned or broken. if everything appears to be correct, i'd start looking at removing the key lock, and see if the key will come out of the cylinder outside of the steering column. in any event, it looks like the OP will need to remove the lock cylinder. removing the key lock cylinder on a C4 is not bad and pretty much can be done, start to finish, in a couple hours. the only issue is the horn contact isolator. mine was very brittle with age, and came out in pieces. new repros are readily available.

edit:

on my 85, button up, in N, the key will not go to the off position, and i cannot remove the key. only way to remove the key is button up and in P. not sure what going on with the OP's shifter/key at this point, but still leaning to a key lock problem..

Joe K

Not sure if this will even help but I couldn't find anything on the 91. This is the diagram from my FSM FOR A 1985. It is not indexed anywhere in the manual. It's just in the automatic transmission section, RPO-MD8., 700-R4, pg 7A-15, Figure 7A-25. My 85 Z51 is doing the same thing but only when cold. The button is extremely hard to depress then when I go to put in park to remove the key I most of the time have to bang on the lever to get the button to pop up. I took the cover off and sprayed WD40 without looking as I could not get the plate to come completely up and it was freezing at the time. I have also sprayed with the tube into the shifter through the opening in the boot. I also removed the button and sprayed into the shaft. These have only been temp fixes as the problem returns. I started a thread on this a couple of months ago and was give the advise to remove the cover and take a look. I am going to do this later. Here's the diagram. HTH

Joe K

Joe C

good info. this may clear things up a bit. same or similar info should apply to the 91. thanks!

FostersPerformance

This is what i was saying....Take the shifter cable that goes to steering column and push it in and see if key comes out. On the diagram, #4 is the spring loaded piece that has to go all the way towards steering wheel for key to come out.
I have a BandM shifter. For now (not on road yet) i have to push the spring loaded piece on column towards steering wheel if i want to take the key out. Good luck!