(Reuters) -- Even in defeat, Carl Icahn can change companies.

Less than a week after Oshkosh Corp shareholders rejected most of a slate of directors backed by the activist investor, a top executive at the U.S. truckmaker feels a sense of urgency to be more responsive to its investors.

Icahn, who owns 10 percent of the maker of military vehicles, said Oshkosh management does not do enough to boost shareholder returns. The company promises to provide investors with clearer benchmarks to measure its performance.

We heard the message that shareholders would like us to provide more targets to measure our progress, Chief Financial Officer David Sagehorn said on a conference call after the company reported better-than-expected first-quarter results. As we go through our fiscal 2012, we will work on ways to provide targets.

He noted that the company wants to improve its overall operating margin by 2.5 percentage points of sales. It had a 4 percent operating margin in the just-ended quarter.

OSHKOSH NOT ALONE

Unlike other U.S. industrial companies such as United Technologies Corp , Caterpillar Inc and 3M Co , Oshkosh does not provide full year per-share earnings targets. Honeywell International Inc and Illinois Tool Works , by contrast, provide quarterly targets.

Instead, Oshkosh provides a broader set of expectations for its four business units, which is similar to the way U.S. automakers Ford Motor Co and General Motors Co have made predictions in past years. They pulled back from giving specific forecasts in the middle of last decade due to extreme volatility in the global auto industry.

General Electric Co takes a similar approach, offering shareholders a framework of how it expects its various businesses to perform and leaving them to do their own math on what that will mean for the company as a whole.

Oshkosh expects sales at its defense arm to fall 15 percent with a 5 percent operating margin. It forecasts revenue at its access equipment unit to rise 25 percent to 30 percent with profit margin in the mid to high single digits.

Substituting for Chief Executive Charles Szews, who the company said was out with the flu, CFO Sagehorn offered no specifics on what sorts of targets the company planned to issue.

We intend along with our chairman, Dick Donnelly, to share your feedback and ideas that we received during this process with the full board and management team and respond over the next few months, Sagehorn said.

ICAHN EFFECT

The promise, however vague, illustrates how even in defeat Icahn can leave a discernable imprint on a company's behavior.

This is what I call the Icahn effect, said Howard Anderson, a senior lecturer at the Massachusetts Institute of Technology's Sloan School of Management. He has studied Icahn's role at companies.

He has an effect on companies even when he does not prevail ... often they start to manage to hit his targets, he added.

Anderson said this often leads to a company executives de-emphasizing the long term performance to make their targets in the shorter term.

Icahn nominated six candidates for the company's 13-member board. At the close of the company's annual shareholders meeting on Friday, Oshkosh said that five of Icahn's nominees had been defeated and that one seat remained too close to call.

The company plans to say this week whether that seat went to an Icahn nominee or a management-based nominee. Even without a board seat, Icahn could continue to agitate for change.

Icahn, who also owns about a 10 percent stake in Oshkosh rival Navistar International Corp , has suggested a merger of the two companies, a proposal that Navistar management has signaled it is open to. He also called on Oshkosh to consider selling its aerial-lifts business, a strong performer in the just-ended first quarter.

While Anderson warned that a shift by management to focus on very short-term performance targets could hurt long-term performance, Morningstar analyst Basili Alukos argued that more openness on big goals like margin targets could help the company.

They could tell us what they think they can get this business's profitability up to, Alukos said. Are they going to provide more detail on the profitability targets of the different units?

If Icahn's involvement encourages that, it would be good news for all shareholders, Alukos said: Anything you can do to improve the long-term performance of a company benefits everyone.

(Reporting By Scott Malone; edited by John Stoll and Derek Caney)

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