According to an Automotive News report citing internal company sources, the 2013 Jeep Grand Cherokee will have an abbreviated model year to make way for a comprehensively-updated 2014 model expected early in 2013.

Dealers began ordering 2013 models this month and production at Chrysler's Jefferson North plant in Detroit will start in August. In anticipation of high demand for the new model, the plant is planning on adding a third shift of 1100 workers in November.

Among the biggest changes for the 2014 model will be an eight-speed automatic transmission built under license from ZF in Chrysler's Kokomo, Indiana transmission plant. The new transmission is expected to significantly increase the Grand Cherokee's fuel economy ratings the way it did for the Chrysler 300 and Dodge Charger sedans in which it was introduced earlier this year.

The other highly-anticipated change is the addition of a diesel option to the Grand Cherokee, an engine choice it hasn't had in the U.S. since 2008. Unlike the last Mercedes-Benz sourced engine, the new 3.0-liter V-6 turbodiesel engine will come from Fiat subsidiary VM Motori. In its current application, it produces 241 hp and 406 lb-ft of torque, figures it shouldn't deviate much from for the Grand Cherokee.

Source: Automotive News (subscription required)