Oshkosh Corp won dismissal of an investor class-action lawsuit alleging the maker of heavy trucks inflated its stock price by failing to write down a troubled Dutch acquisition fast enough.

U.S. District Judge William Griesbach in Milwaukee said it was not credible to believe the company and its auditor, Deloitte & Touche, intended to defraud anyone about Geesink Norba Group, a garbage truck maker that Oshkosh bought in 2001 for $137.6 million, including $95.6 million of goodwill.

Geesink suffered $40.8 million of losses over four and a half years starting in 2004 before Oshkosh finally announced a $175.2 million writedown on June 26, 2008. Oshkosh stock fell 33.5 percent that day, to $22.29 from $33.51.

According to plaintiffs led by the Massachusetts Public Pension Funds, it should have been obvious by 2003 that the acquisition was a failure, given Geesink's sales and management problems, and Oshkosh should have taken a writedown sooner.

But in his 44-page ruling on Tuesday, Griesbach said it is simply not plausible to infer that any of the defendants intended to defraud anyone, given the true and extensive financial data they did disclose and the consistent red flags they issued about a potential impairment to goodwill.

Griesbach dismissed the case against the Oshkosh, Wisconsin-based company with prejudice, meaning it cannot be brought again.

Lawyers for the Massachusetts funds and for Deloitte did not immediately return calls seeking comment. Oshkosh Chief Executive Robert Bohn said the company is pleased with the ruling.

Noting the Tolstoy-esque length of the 192-page complaint, Griesbach said the plaintiffs nonetheless made only generalized fraud allegations, asserting simply that Oshkosh overpaid for Geesink and that everything it said about the company over the 4-1/2 year period was a lie.

But he said Oshkosh repeatedly warned both that a goodwill writedown might be needed if Geesink's business did not improve, and of the business risks tied to the 93-year-old company's first significant foray into Europe.

This is not the case of a horse-and-buggy company bullheadedly insisting that good times are around the corner despite the mass appeal of the automobile, Griesbach wrote.

Geesink was a company in flux, in a foreign market that was in flux, and it was run by an ever-changing management regime, he added. It is reasonable to question the decisions that management made, but given the complexities of the business, an assertion that they committed fraud requires more than the cut-and-paste job found in the amended complaint.

Oshkosh shares closed Tuesday at $40.50.

The case is Iron Workers Local No. 25 Pension Fund et al v. Oshkosh Corp, U.S. District Court, Eastern District of Wisconsin, No. 08-797.

(Reporting by Jonathan Stempel; editing by John Wallace)