The combined company, to operate under the Aamco name, will be 83 percent owned by American Capital Strategies Ltd. of Bethesda, Md., a publicly traded investment company. American Capital acquired Cottman for $46 million in 2004.

The new Aamco will continue to provide transmission repair and expanded automotive services. Cottman centers will switch to the Aamco name.The combined company, to be based in Horsham, Pa., will employ more than 6,000 people and have annual sales of about $600 million.