The van sometimes makes a mild clunking noise (in what sounds to be the rear end or tranny) when I go forward from a stop.
Noises are one of the most difficult of issues to diagnose without being able to actually hear it. The vehicle could be put on four jack stands. Allow someone to operate the vehicle while you listen for the location of the noise. I often use a stethoscope to pinpoint internal noises such as a mild clunking noise. I looked up a Mechanic Stethoscope in case you would like one of your own. As an Amazon Associate I earn from qualifying purchases. Please follow link to purchase.