Have a 1987 Monte Carlo LS 4.3L stock. ~130,000 original miles. Floor shifter, also stock. There is a metallic clunk when it is shifted into gear from park. Forward or reverse does not matter. This sound occurs when the lever reaches the gear it is to go into. The car is not moving yet when this is heard. I leave the car at idle when shifting. Car idles at the correct RPM. There is no issue with drivability. The indicator is off a bit and does not point directly at the gear but has been since I replaced the bulbs in the dash prior to this problem. It sounds like two steel bars hitting against each other. transmission shifts fine when driving with no unusual sounds.