Make sure that YOU look at your 5th wheel to make sure its locked in when you hook up, and dont take anybodys word for it. I asked my father in law if it locked when I backed under and he said "yeah, it locked". He lifted the jacks, I pulled ahead and BAM!!
My heart sank. I got lucky tho. My pace edwards rails took one hell of a beating, and spared my body from any seriously noticable damage. I will look for myself from now on. Oh, when it dropped he said "It must not have locked." Well, I kept my cool and all is good.