If the tinny sound is really bugging you, you can remove the trim and the moisture shield and spray the inside of the shell with sound deadening material, also know as spray under coat. This sounds like an aftermarket shell. OEM doors come with the material in palce.
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.