* Wall St extends pullback after worst week of the year
* Earnings, economic worries offset monetary stimulus
* Lufkin stock jumps almost 38 pct on GE's plan to buy company
* Dow off 0.4 pct; S&P 500 off 0.1 pct; Nasdaq down 0.1 pct
By Angela Moon
NEW YORK, April 8 (Reuters) - U.S. stocks slipped on Monday as investors faced the prospect of a lackluster corporate earnings season, which could challenge the market's recent record high, and an economy that could be hitting a slow patch.
The early pullback extended Friday's decline that had pushed the S&P 500 into its worst weekly percentage loss for the year. Defensive shares led Monday's downside move, including the S&P telecommunications sector index, off 0.7 percent.
Financial stocks also fell, extending last week's slide. Goldman Sachs shares lost 1.1 percent to $142.09. Wells Fargo & Co shares dropped 0.9 percent to $36.80.
Earnings forecasts have been scaled back, heading into first-quarter reports. S&P 500 companies' earnings are expected to have risen just 1.6 percent from a year ago, according to Thomson Reuters data, down from a forecast in January calling for a gain of 4.3 percent.
Stocks have rallied strongly this year with major indexes hitting record highs, helped in part by the Federal Reserve's stimulus program. The S&P 500 is up nearly 9 percent for the year so far, while the Dow has gained just under 11 percent.
The S&P 500 "had its worst week of the year. Still, it would be premature to conclude that the party is over," said Jerry Webman, chief economist at OppenheimerFunds.
"The index remains reasonably valued by a range of metrics. Constituents' earnings and sales multiples are still lower than they were at either of the last two market peaks, and cash on companies' balance sheets is higher."
A worse-than-expected jobs report on Friday added to fears that the pace of economic growth could be softening after generally upbeat data at the start of the year.
But loose monetary policy from central banks around the world still makes equities attractive to investors and pullbacks could be used as buying opportunities, analysts said.
The Bank of Japan started its bond purchases on Monday after it announced last week it will inject about $1.4 trillion into the economy in less than two years.
Fed Chairman Ben Bernanke will give a speech later on Monday after markets are closed. Investors have been watching for any insight into the Fed's thinking on how long the central bank will keep its asset purchase program in place as it tries to boost the economic recovery.
The Dow Jones industrial average slipped 51.28 points, or 0.35 percent, to 14,513.97. The Standard & Poor's 500 Index shed 1.50 points, or 0.10 percent, to 1,551.78. The Nasdaq Composite Index dipped 2.75 points, or 0.09 percent, to 3,201.11.
General Electric Co said it will buy oilfield pump maker Lufkin Industries Inc for about $2.98 billion, sending Lufkin shares up nearly 38 percent to $88. GE, a Dow component, slipped 0.4 percent to $22.85.
Among blue-chip stocks, Johnson & Johnson Inc was the Dow's biggest percentage decliner after JPMorgan downgraded the healthcare company's stock to "neutral" from "overweight," saying Johnson & Johnson was facing "a messy first quarter and a likely downward revision to 2013 guidance." The stock fell 1.5 percent to $80.81.
Among technology stocks, HP shares shed 0.7 percent to $21.81. Google Inc lost 1.3 percent to $772.75.