About 3,000 black autoworkers returned to work Monday after staging a 10-day strike in defiance of their union to protest divestment arrangements made by Ford Motor Co. The wildcat strike began April 15 at the South African Motor Corp.'s main plant in Pretoria. The company, known as SAMCOR, said its entire paid-by-the-hour workforce joined the strike, and the production loss was estimated at between 1,800 to 2,000 vehicles. The workers were protesting an agreement signed last year by Ford, SAMCOR and the National Union of Metalworkers under which Ford donated the bulk of its minority holding in SAMCOR to a trust administered by the workers. The trust was intended to fund development projects in the communities where the workers live. But the workers maintain they should receive the dividends directly. According to an industry source who spoke on condition of anonymity, the strikers decided to resume work while negotiations with the union continued to resolve the dispute over the dividends. The union had no immediate comment on the matter. Prior to its disinvestment late last year, Ford owned 42 percent of SAMCOR. The corporation was formed in 1985 when Ford and Anglo American Corp., South Africa's largest conglomerate, merged their South African auto operations.