-- General Motors Co. continued to trim its senior management ranks with the retirement of four senior executives, but filled out its board of directors with the naming of five new members appointed by the U.S. Treasury Department and Canadian government.

GM said Thursday that Gary Cowger, group vice president of global manufacturing and labor relations, will retire at the end of the year, as will Troy Clarke, group vice president and president of GM North America. GM CEO Fritz Henderson will assume Clarke's responsibilities.

Cowger and Clarke will be joined in retirement by Ralph Szygenda, group vice president and chief information officer, who will leave Oct. 1. And the company's highest ranking woman executive, Maureen Kempston Darkes, group vice president, GM Latin America, Africa and Middle East, will retire at year's end. Her departure leaves GM with no women as group vice presidents.

GM, which came out of bankruptcy protection July 10, is making the changes as part of its continued restructuring.

The new members of GM's board of directors include several former CEOs with a decidedly telecom bent, including the former heads of Nextel, AT&T and Alcatel-Lucent. The Canadian board member representative is a former head of Lucent's Canadian arm. Several members also have connections to airlines and railroads but none has experience in the auto industry.

New board members include Daniel F. Akerson, a managing director of private equity firm, the Carlyle Group, and a board member at American Express. Like GM's new chairman, former AT&T CEO Edward Whitacre Jr., Akerson is a telecom veteran. He was chairman and CEO of XO Communications. Before that, he served as chairman and CEO of Nextel Communications Inc.

"The members of this new board bring immense experience and diverse perspectives to the table, and that's exactly what GM needs," Whitacre said.

GM's new board members were approved on Monday in a conference call with Treasury and Canadian officials. The new board will hold its first meeting in Detroit in early August.

David Bonderman, a founding partner at TPG Capital, is a former corporate lawyer who has served on a number of boards, including the Wilderness Society, Continental Airlines and Ryanair Holdings PLC. Bonderman's TPG Capital and other investors bought half of Washington Mutual last year at a hefty discount, only to see the bank collapse in bankruptcy. TPG lost $1.3 billion in the deal.

Also named to GM's board were Patricia F. Russo, a former CEO at Alcatel-Lucent, and Robert D. Krebs, a former CEO of railroad conglomerate Burlington Northern Santa Fe and member of UAL Corp.'s board, which is the parent to United Airlines.

Canada named to the board Carol Stephenson, dean of the School of Business at the University of Western Ontario and a former CEO of Lucent Technologies Canada. Canada has infused $9 billion into GM and has an 11.7 percent equity stake.

Board members will receive $200,000 in cash yearly, plus a company car. The chairman will receive $350,000 a year. They join the UAW's health care trust fund appointee, Steve Girsky.

They also join five members of GM's old board: Erroll Davis Jr., chancellor of University Systems of Georgia; Nevill Isdell, a retired Coca-Cola Co. CEO, Kent Kresa, former Northop Grumman Corp. chairman; retired Ernst & Young LLP CEO Philip Laskawy and Kathryn Marinello, chairman and CEO of Ceridian Corp.

Also on Thursday, the company finalized its eight-member executive committee that replaces two large auto strategy and product boards and will be responsible for making key decisions about the company's future.

And it announced that Bryan Nesbitt, vice president of GM North America design, is now general manager of the Cadillac brand.

Other changes within the company include the appointment of Brent Dewar, who is GM Europe's vice president, sales, marketing and aftersales, as vice president for the global Chevrolet brand. Ed Peper, currently GM North America vice president, who oversees Chevrolet operations, will be named general sales manager for Cadillac sales.

Tim Lee, currently GM North America vice president, manufacturing, will become a group vice president, responsible for global manufacturing and labor.

Terry Kline, currently process information officer, product development, will be named vice president, information systems and services, and chief information officer.

"With these announcements, most of the new GM leadership team is in place," Henderson said. "We expect to have the final round of announcements next week."

Those final management changes will help GM slim its executive ranks by 35 percent.