There's a virtually identical thread about this with a post by dougrainer about making a shim from a flat washer. Try and "advanced search" on this Tech Issues Forum. The fix sounds cheesy, but it links to a manufacturer's bulletin, and both dougrainer then the OP found it worked.
EDIT: Oh... I looked a this thread before and doubt the fix I just noted, will be enough to fix it. If it DOES apply, you may fix your current issue and find it'd be helpful to also shim it. Either way, I think somebody will be along to help.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB