Sounds like you may have a broken sway bar link. Just happened to notice
that Van Cafe has them (www.volkscafe.com) get's you there.

On Sat, Jun 13, 2009 at 4:59 PM, John Rodgers <inua@charter.net> wrote:

> Recently I have begun to experience an occasional loud, severe "Bang" up
> front - so severe it shakes the front end of the van. It does it at slow
> speed, usually after a stop or slowing down. Or - after being stopped,
> and stating off again - particularly when beginning or ending a turn of
> the type in turning the corner at a stop light. It feels like the van
> has been hit by a sledge hammer somewhere solid - not in the sheet metal
> - but maybe in the suspension components or the chassis up front. I just
> had my mechanic check this and he found nothing.
>
> Any ideas?
>
> Thanks,
>
> John Rodgers
> 88 GL Driver
>