General Motors ( GM) put its Allison Transmission commercial and military operations on the block Thursday.The giant automaker said it is "looking at strategic options ... including a potential sale of the business." Allison Transmission designs, engineers, manufactures and sells automatic transmissions for commercial and military vehicle applications. It employs 3,400 people and has seven plants in Indianapolis. GM called the sale process "another potential step in GM's plan to improve liquidity through the assessment of strategic options for a business that is not central to GM's mission of designing, manufacturing and selling cars and light trucks globally. GM continues to have a strong liquidity position, with more than $20 billion in cash and marketable securities at the end of the third quarter 2006." The news comes the same day as rival Ford ( F) posted a $12.7 billion loss for 2006.