The Chrysler Group plans to produce a smaller version of its 3.6-liter Pentastar V6 engine, likely at a plant in suburban Detroit, according to a union official and a source familiar with the project. The new 3.2-liter Pentastar V6 is set to debut in the replacement for the Jeep Liberty, the union official said. Chrysler-Fiat CEO Sergio Marchionne has said the Liberty successor will be introduced in January at the 2013 Detroit auto show. Bruce Baumhower, president of UAW Local 12 in Toledo, Ohio, where the Liberty replacement will be assembled, said the vehicle is expected to have a 3.2-liter V6 Pentastar and a nine-speed transmission. The transmission was developed by ZF Friedrichshafen AG, which provides the eight-speed transmission for the Dodge Charger and Chrysler 300 sedans. Baumhower made the remarks to Automotive News on Wednesday and to Toledo TV station WTVG this week. Another source familiar with the project verified Baumhower\'s information. A Chrysler spokesman said the automaker would not discuss future product or production plans. Work has begun on a $500 million renovation to the Toledo North Assembly plant to make the successor to the Liberty. The plant will close in early August for at least five months to retool for the new SUV, Baumhower said. The automaker aims to improve its corporate average fuel economy, in part with new transmissions. Marchionne hints \"You should not underestimate the weight of transmissions\" to improve fuel efficiency, Marchionne said on the sidelines of the Geneva auto show this month. \"If we had known the eight-speed [automatic transmission] was coming, we would have made the [3.6-liter] Pentastar a 3.2-liter\" engine. Chrysler has spent much of the last year removing tooling and equipment from the Trenton North Engine plant in suburban Detroit, a Trenton city official said. About 80 percent of the 2.1-million-square-foot plant is vacant, with the rest used to make engine parts for the 3.6-liter Pentastar. The adjacent Trenton South Engine plant has been building the 3.6-liter Pentastar since its launch in March 2010, and along with a twin plant in Saltillo, Mexico, has been struggling to keep up with demand. Trenton South and Saltillo are each designed to produce about 440,000 engines per year, but Marchionne said the automaker needs as many as 1.2 million Pentastar engines per year to meet demand. The 3.6-liter Pentastar is available in 11 vehicles across the Chrysler Group lineup, producing between 283 and 305 hp, depending on the vehicle. It comes standard on several of the automaker\'s highest-selling vehicles, including the Jeep Wrangler, Chrysler Town & Country and Dodge Grand Caravan minivans, and its flagship sedans, the Chrysler 300 and Dodge Charger. The Pentastar also will make its debut this year in the Ram 1500 pickup. Projects under way Trenton South assembled the 1 millionth copy of the Pentastar on Jan. 27, about 18 months after its introduction. In June 2011, Chrysler invested $114 million into the Trenton North plant to begin making parts for the 3.6-liter Pentastar in about one-fifth of the plant. Chrysler plans to replace seven V6 engines with displacements of between 2.7 and 4.0 liters with Pentastar engines. Two of the outgoing engines, with displacements of 3.8 and 4.0 liters, were assembled in the Trenton North plant before it closed in May. The first hint that smaller-displacement Pentastars may be on the way occurred in November 2009 when the automaker laid out its five-year product plan. At the time, Chrysler said it was considering two versions of a 3.3-liter V6, including one with Fiat\'s Multi-Air technology. The automaker has not yet introduced Fiat\'s Multi-Air technology to the Pentastar, but plans to do so. Multi-Air uses small hydraulic pumps, along with a computer, to control the timing of each air intake valve of an engine to improve fuel efficiency and power and reduce emissions.