General Motors Co. contributes 60.6 million shares of company stock valued at $2 billion to its hourly and salaried pension plans as previously planned, further trimming the restructured auto maker’s biggest financial liability.

GM also paid $4 billion into its pension plans in December. The company closed 2010 with its U.S. pension plans underfunded by $17.1 billion. Its non-U.S. pension plans reportedly were $10.3 billion short of obligation.

Executives at the North American International Auto Show in Detroit this week told journalists the auto maker would like to completely erase its debt as soon as possible, which would mark a spectacular financial turnaround for a company massively leveraged before its 2009 bankruptcy.

GM already has impressed Wall Street by earning some $4.2 billion over the first three quarters of 2010.

A fourth-quarter profit is expected in the coming weeks that would push the auto maker to its first annual profit since 2004. However, executives have warned GM will not make as much money in the October-December period as the previous three due to costly items such as production ramp-ups of key new products.

With today’s contribution, 40.4 million GM shares went to the hourly plan and 20.2 million to the salary plan.

“We continue to take the steps necessary to lower our risk profile, so our focus can be on designing, building and selling the world’s best vehicles,” GM Vice Chairman and Chief Financial Officer Chris Liddell says in a statement.

GM’s returned to public trading in November with a record initial public offering. The stock inched higher today on news of the contribution, to $38.29 in mid-morning trading.