[1986nate]

I'm betting the rubber mounts and bushings almost everywhere are probably needing replacement at that mileage. The rubber starts breaking down from age mostly and starts cracking and getting hard and stops doing its job correctly. Take a look at the rear diff bushings, trans mounts, etc.

One thing to try, is while someone else puts the car from P to R and also to D while you look underneath the car, you can see just from the torque transfer how much movement there is.