American Axle posted a loss of $644.3 million in the second quarter, or $12.49 per share, against net income of $34.6 million a year earlier, or 66 cents per share.

Revenue fell to $490.5 million from $916.5 million a year earlier.

The company was hurt by a three-month strike by its 3,650 hourly workers represented by the United Auto Workers, which ended in late May. The strike reduced its second quarter sales by $274.9 million and its operating income by $86.6 million.

The quarterly loss also reflects $575.6 million in one-time special charges, relating to attrition programs, unemployment benefits, inventory writedowns, asset impairment among others.

The UAW ratified a new cost-cutting contract in May, ending a strike that had at least partly idled about 30 General Motors Corp plants due to parts shortages.

Under the contract, American Axle is cutting hourly wages by almost 40 percent and offering "buydown" payments of up to $105,000 over three years for workers who remain in return for accepting lower wages. It is also providing UAW-represented workers with buyout packages of up to $140,000.

But the Detroit-based supplier remains under pressure as the market for gas-thirsty large trucks and SUVs, for which it supplies parts, has tumbled more rapidly in the past two months.

In 1994, GM sold off plants to an investor group that created American Axle, which derived more than 70 percent of its revenue from the No. 1 U.S. automaker in the second quarter.

GM's U.S. sales were down 16 percent year-to-date through the end of June, led by a 21 percent drop in truck sales.

(Reporting by Soyoung Kim; Editing by Derek Caney)