General Motors Corp. reins in its 2009 U.S. industry sales forecast, perhaps the most significant planning assumption in the auto maker’s viability plan as it undergoes government oversight in return for $13.4 billion in taxpayer loans.

GM tells Wall Street analysts in Detroit today it is planning for a total U.S. sales market of 10.5 million vehicles, or 1.5 million fewer units than the 12 million the auto maker assumed in a viability plan submitted to Congress Dec. 2.

U.S. sales in 2008 plunged to 13.2 million units, excluding medium- and heavy-duty vehicles, from 16.1 million in 2007, according to Ward’s data.

GM’s 2009 revision brings its forecast closer to Chrysler LLC’s bottom-line projection of 10.1 million units. Chrysler also is under government scrutiny for its $4 billion assistance claim.

Ford Motor Co., which has not applied for loans but has said it may ask for a $9 billion line of credit should the economy worsen this year, expects U.S. sales of 12 million to 12.5 million.

GM now forecasts global industry sales of 57.5 million vehicles, more than 6 million units less than the 63.8 million it projected in the Dec. 2 plan. The industry gets a closer look at the auto maker’s global sales for 2008 when it reports detailed results next week.

GM says it is changing its prior forecast submitted to the government to ensure the plan’s success “even in the most challenging of markets.”

“We are on track to accomplish the requirements of the viability plan,” GM Chairman and CEO Rick Wagoner says in statement. “We know we have a lot of work in front of us, but we are already working closely with many key stakeholders. The GM team is 100% dedicated to achieving the goals of our plan.”

Negotiations between GM and the United Auto Workers union over lowering labor costs, as mandated by the government-loan agreement, began this week. GM also will meet with its dealers and bondholders to win concessions.

The auto maker says it will continue to refine assumptions within its viability plan as the next two years unfold.

“At this juncture, I don’t think anyone can project sales,” Fritz Henderson, GM president and chief operating officer, says during a webcast of the analyst meeting today. “The best thing we can do is develop a plan around conservative estimates. We’re trying to be very conservative.”

The company will submit its revised plan to Congress Feb. 17, which will include an update on concessions from key stakeholders and likely determine whether the auto maker will receive additional government loans.

GM received a $4 billion loan in December and expects $5.4 billion later this week. The remainder would come after Feb. 17.

Meanwhile, Ford confirms it has entered discussions with the UAW but declines to reveal whether the talks are aimed at securing labor-cost concessions in line with those sought by Chrysler and GM.

“It’s in our best interest that we continue to take the steps necessary to remain competitive in the near and long term,” spokeswoman Angie Kozleski tells Ward’s. “We’re looking at opportunities, but we haven’t said what we’re looking for. However, we have to be competitive with both our domestic competitors and the transplants.”

Since it submitted its plan to Congress Dec. 2, Chrysler has been in talks with the UAW at various levels. However, neither the auto maker nor the union has been willing to elaborate.

Harley Shaiken, a labor expert at the University of California-Berkeley, says it is unlikely Ford is seeking similar concessions as GM and Chrysler.

“What Ford would like to do, and what the UAW would like to do, is to ensure Ford is competitive, rather than seeking to match what has yet to be negotiated,” Shaiken tells Ward’s. “(Ron) Gettelfinger has made it clear he’s not reopening negotiations.”

Even if GM and Chrysler do end up securing labor concessions from the UAW, it doesn’t mean Ford automatically will receive the same givebacks, Shaiken says, noting in the past the union has tailored its agreements specifically to each auto maker.

Although the government has said GM and Chrysler must get their labor costs in line with the foreign transplants as a condition of the federal loans, Shaiken says there is a “lot of room for interpretation” in the agreement.

“The major difference in total compensation costs is legacy costs, particularly retiree health care,” he says. “If that’s deferred, you could make an argument they’re close to parity already.”

– with Eric Mayne