2011 Jeep Grand Cherokee

Jeep Grand Cherokee sales are up 37 percent through April, and Chrysler has already sold nearly 50,000 units in 2012, placing the flagship Jeep model ahead of all other Pentastar vehicles, save for the Ram pickup.

That demand will be keeping the Jefferson North assembly plant in Detroit open through the July 4 holiday period, according to The Detroit News. Big Three plants have traditionally shut down for two weeks in July to facilitate model-year changeover, though that process will be accomplished with the lines running this year, according to the report.

Jefferson North is already running overtime including some Saturdays to keep up with demand for both the Grand Cherokee and the Dodge Durango. Sales of the Dodge model are up seven percent this year.