Rye, N.Y.-based Gabelli Asset Management, which owns about 8.6% of the company's shares, proposed the plan, which would rescind a takeover defense to make it easier to consider offers for the company.
The proposal received 79% of the 43.1 million shares voted at the company's annual meeting in Chicago. The board will take the request under advisement to discuss at its next board meeting, Chairman John Horne said.
The vote comes a week after Navistar and Ford Motor Company said they will form a venture to build commercial trucks and cooperate on diesel engines for Ford vehicles. Navistar last week also unveiled the International 4000 Series of "High Performance" trucks.
Navistar shares have fallen 25% over the past twelve months. The company this week also announced a first-quarter loss of $35 million and cut its forecast for heavy-truck sales for fiscal year 2001.
A poison pill defense, which Navistar's board approved in April 1999, makes it expensive for a suitor to take over a company without its board's approval. Without a poison pill defense, a suitor could come in and buy Navistar at an undervalued price.