When the vehicle is not warm the AC compressor slightly vibrates when running......When the vehicle is warm the AC compressor vibrates like crazy when running... (You can even feel it through the pedals and floorboard)......I pulled this AC compressor from my blown and put it on the new engine not to long ago. It’* always operated poorly...It has no leaks of any kind.

I have a feeling I will be buying a new compressor and all the other essentials....

With the belt off how does the AC pulley turn? Is the compressor loose at all?

The pulley turns easy....I did not notice any movement on the compressor...........When I pulled the compressor off the bad engine, I never refilled it back with ac oil.......I couldn't tell you if this compressor was this way before the original engine died...I bought this vehicle with the bad engine...I have done a lot of work on this Bonny (New engine, 4 solenoids for tranny, etc...)

never put refrigerant back in it?

I put refrigerant back in it....just not any lubricating oil..........When I did moms Northstar motor, I made shure I put some PAG oil in the AC compressor before reinstalling it.......Her air runs perfect