1997 Mercury Marquis shift linkage

This car literally gets driven about 2500 miles a year. It looks brand new and drives brand new but a bolt backed out of the shift linkage. We'd noticed play in the shifter then eventually a star headed brass bolt appeared on the floor. I took the various panels out and let the steering wheel drop down and rest on the seat and found where the missing bolt belonged. I put it back and thought this was finished but it's back. I'm guessing the bolt is backing out and or that there is a 2nd bolt that's also either backing out or missing. It's basically where the shifter links up to the section I'm guessing goes thru the firewall. It's brass and like a small plate coming together. When I initially replaced the bolt it was fine but it's only been a couple of weeks and literally only 60 miles or so and there is play in the shifter. Last time if stopped going into park and that to me is an accident waiting to happen. Is there a 2nd bolt I missed tightening or could these plates be bent? Also should I have simply used Locktite? I see many questions about sifting on LTD's and Grand Marquis' but I do not know if they relate to this plate. It's about midway down the steering column. I did not use Locktite last time since I saw no residue of Locktite. Clearly I missed something. Thanks, Marvin