Chrysler Group LLC, the automaker run by Fiat SpA, is forging ahead with summer shutdowns at some factories and canceling overtime at a plant in Mexico to conserve parts from suppliers affected by the March earthquake in Japan.

The automaker, based in Auburn Hills, Michigan, will idle some factories in Ohio and Michigan in June, instead of July, Jodi Tinson, a Chrysler spokeswoman, said in an email Thursday. The factories make pickups and sport utility vehicles. U.S. automakers typically stop production for a week or two to change tooling before the next model year's production.

Chrysler's Toledo North assembly plant that builds Jeep Liberty and Dodge Nitro SUVs in Ohio will shut down during the weeks of June 20 and June 27 instead of during the weeks of July 11 and July 18, she said. The Toledo Supplier Park that produces Jeep Wranglers will shut down for the week of June 20 instead of the week of July 11, Tinson said.

A factory that makes Ram 1500 and Dakota pickups in Warren, Michigan, will be closed during the weeks of June 20 and June 27 instead of July 11 and July 18, she said.

The Ram truck plant in Saltillo, Mexico, will eliminate overtime for May 20, May 27 and June 10 and June 24.