Metal shavings in the transmission differential? on 2003 Volkswagen EuroVan

A mechanic has said there ahas gone bad in my Eurovan 2003. Says it needs a new transmission (very expensive), but should this be true? Another mechanic said the transmission mount was broken? Don't know who to believe? The problem is when I begin driving or start up from a stop sign or wherever, I hear a kind of grinding, rough noise that bothers me.

Asked by for the 2003 Volkswagen EuroVan