Dodge has produced some vehicles with Cummins diesel engines for the Canadian market.
Cummins and DaimlerChrysler have recommended that diesel concentrations of up to 5% (B5) should not cause any problems.
For the 2007 model Dodge has approved diesel of up to 20% (B20) for government customers. It is not yet clear if this warranty approval will extend to the general public.
Some background:
http://www.cummins.com/na/pages/en/customerassistance/faq/answers.cfm?uuid=000947AD-64AE-1B8D-BCF080C4A8F00000
http://www.biodiesel.org/resources/pressreleases/fle/20060123_DCXapprovesB20inDodgeRam.pdf