I purchased two of the plug door reefers, and they have the same coupler issues described in this thread. I thought the defective couplers on the two reefers I received were an isolated problem so I got an RMA and sent them back for repair (I included a detailed letter outlining all of the problems I was experiencing). Lionel replaced the trucks and after testing them said they "worked good." The replacement trucks/couplers still do not work with existing Lionel products, so I am confused about them saying they "work good."
I am hopeful Lionel will offer a replacement coupler solution because these are good looking cars and I'd like to run them.
Like others I'm holding off buying any new Lionel equipment until the issue is satisfactorily resolved.