95 blazer rolls in park

My 95 blazer w/auto trans 4X4 just started this: I can shift into all gears, but when shifting into Park, the luminous indicator goes dark, the tranny does not go into park (the vehicle actually rolls when pushed) and I can hear a slight clicking noise as the vehicle rolls. I found this out whe trying to park in y driveway which is pitched at ~20 degrees. I cannot start the car in Park, I have to turn the key to the ignition position and shift into neutral to start the car. Tranny functions normally otherwise.

Check the linkage underneath the truck. It is probably out of adjustment just enough to not quite grab.
I had the same problem in my old Lemans. Re-adjusted the linkage and all was well again.

Check the linkage underneath the truck. It is probably out of adjustment just enough to not quite grab.
I had the same problem in my old Lemans. Re-adjusted the linkage and all was well again.

Yip, what he said.

Also, be nice to the shifter and don't slam it into park or into drive.

Thnaks for the replies! I will check.