REFILE-UPDATE 2-CSK Auto reports unexpected third-quarter loss

(Refiling to remove extraneous word "to" in headline) (Adds stock decline, Wall Street forecast, background)

BOSTON Dec 18 (Reuters) - CSK Auto Corp CAO.N, a retailer of car parts, posted an unexpected third-quarter loss on Tuesday as sales declined, sending its shares sharply lower.

The company reported a net loss of $5.8 million, or 13 cents per share, compared with a profit of $3.2 million, or 7 cents per share, a year earlier.

Excluding one-time items, the loss was 10 cents per share, according to Reuters Estimates. On that basis, analysts' average forecast was a profit of 9 cents per share.

The Phoenix, Arizona-based company said net sales fell 2.4 percent to $471.4 million, and sales at stores open at least a year fell 3 percent. It attributed the decline in revenue to a lower number of transactions, partially offset by a higher average per-transaction value.

CSK shares were down 41 cents, or 7.7 percent, to $4.89 in morning trade on the New York Stock Exchange after falling as low as $4.15 earlier in the session.

The shares have tumbled 74 percent this year as the company has delayed filing financial statements with the U.S. Securities and Exchange Commission and announced plans to close about 40 stores next year.

As of Nov. 4, the company operated 1,342 stores in 22 U.S. states. (Reporting by Scott Malone in Boston and Emily Chasan in New York; Editing by Mark Porter and John Wallace)