DaimlerChrysler and General Motors have signed a definitive agreement to jointly develop hybrid powertrains. The agreement was originally announced in December 2004, and finalized early this week. DaimlerChrysler will lead the development of hybrid powertrains for rear-wheel-drive luxury cars. GM will take the lead for rear-wheel-drive full-size trucks, sport-utility vehicles and front-wheel-drive vehicles. The first hybrids under the plan, the Dodge Durango and Chevrolet Tahoe, are expected out in late 2007.