* Grand Cherokee gets optional diesel, eight-speed transmission
* Small changes intended to tide Jeep over till summer
* Replacement for compact Jeeps due in 2014
By Paul Lienert
DETROIT, Jan 14 (Reuters) - Chrysler's Jeep brand will introduce updated versions of its best-selling Grand Cherokee and compact Compass and Patriot this week at the Detroit auto show, and the 2014 models will hit dealer showrooms in early spring.
The upgrades include mild facelifts for the Grand Cherokee and Compass and a new diesel engine option and eight-speed automatic transmission for the Grand Cherokee. Compass and Patriot will offer a new six-speed automatic.
Chrysler's Italian parent Fiat SpA is pouring billions of dollars into Jeep to expand the product range and boost the brand's overseas presence.
The modest changes that will be seen at the auto show are expected to tide Jeep over until its next all-new model, a replacement for the now-defunct Liberty, begins production this summer at the massive Jeep complex in Toledo, Ohio.
Built in Detroit, the Grand Cherokee is Jeep's best-selling model. Sales last year jumped 21 percent, to 154,734.
The 2014 Grand Cherokee features a mildly revised front end and will add a new top-of-the-line Summit edition.
The optional 3.0-liter six-cylinder EcoDiesel engine delivers 240 horsepower and 420 pound-feet of torque, and is mated to an eight-speed automatic transmission with paddle shifters behind the steering wheel. The EPA rates the Grand Cherokee diesel at 21 miles per gallon in city driving and 30 m.p.g. on the highway.
A full redesign of the Grand Cherokee is not expected until 2016, according to industry suppliers familiar with the company's plans. Chrysler also plans to add a larger, more luxurious seven-passenger derivative in 2014 that will resurrect the Grand Wagoneer name.
The 2014 Compass gets a few small exterior and interior updates, while the 2014 Patriot has been left mostly untouched, with the exception of the new transmission.
Both models share a common passenger-car platform that also was used by the now-discontinued Dodge Caliber. They have been slow sellers for Jeep, with combined sales last year flat at 102,000.
Chrysler plans to replace both the Compass and Patriot with a single compact model in 2014 that could share a common underbody architecture with the Fiat-based Dodge Dart sedan, the sources said.