While backing out of parking space, Sudden (any accel.)rattling, clanking sound!

What is your question?

1992 Ranger Ext cab 2wd. We are 2nd owners. 176K mi. ~ out of nowhere, my son was driving to work, he called to say the "rear end" sounded odd? I had driven it all wk, no prob? Then later, after parked for 8hrs, it RATTLES & CLANKS@any acceleration. Driving it vibrates & sounds like noise is coming from the rear. Outside it sounds like LOUD BB's & clanking metal?