if not snapped it will be torsion bars that have been removed to replace rear suspension bushes and put back in wrong position! you could try jacking up van till little or no weight on rear susp [you will need shocks off or disconnected] in end of torsion bar is i think a 10mm or 12mm thread to which you could attach a slide hammer to pull out bar then you could re-position it. they are very tight you may end up taking axle out to cure your problem! awful job [speaking from experience takes, a good day to replace bushes].
k, November 2008