NEW YORK -- Can it really be true that Donald Trump, a man whose signature alone was enough to get him a $135 million loan from the nation's largest bank, can't pay his bills?

Trump's current cash crunch, which has forced him into marathon negotiations with bankers over how to manage an estimated $3 billion in debt, has revealed the business shortcomings of a tycoon who may have been better at promoting himself than at mastering the arts of pricing property and controlling costs, according to bankers and industry analysts. It has also focused attention on Trump's lenders and Wall Street backers, who admit in hindsight that they may have allowed their celebrated customer to trade more on his name than on the profits he was likely to produce.

Trump earned his early reputation as a savvy business trader the old-fashioned way, with a string of financial successes such as the development of the Grand Hyatt hotel, hard by Grand Central Station, and Fifth Avenue's Trump Tower. Both are still moneymakers.

But as his reputation grew, and with it his appetite to feed the publicity machine, Trump borrowed huge sums of money to take on increasingly expensive and daring projects. He purchased a 76-acre tract on Manhattan's Upper West Side on which he hoped to build a new urban village, including the world's tallest building, despite the likelihood that the project would face strong opposition from the local community. And earlier this year, he opened the giant, opulent Taj Mahal casino, right down the boardwalk from two other Trump casinos, despite plenty of evidence that the Atlantic City market was stagnant.

"If you don't have an ego that you have to keep feeding, you don't just keep buying everything big that's in sight," said Abraham Wallach, senior vice president of First Capital Management Ltd., a New York-based real estate firm. "We see the same properties he does. We could have bought the Plaza Hotel. We thought it was too expensive."

Trump has declined this week to talk about his troubles. While he has won much praise for his $50 million renovation of New York's Plaza Hotel, many in the hotel industry were surprised by the $390 million he paid for the landmark two years ago. According to industry estimates, Trump's debt payments on the Plaza currently exceed its earnings by about $20 million a year. On today's market, they estimate, Trump would be lucky to get back what he put into the hotel -- and could lose as much as $100 million.

In recent years, business analysts say Trump's portfolio has come to include other assets that have proven to be less than solid earners, at least so far. And in private, the bankers and bondholders who lent Trump his billions to buy are now asking themselves whether they were too ready to accept the illusion of invincibility Trump created for himself with the help of his mansions, his yacht and the other highly publicized trappings of a posh lifestyle.

"He looked so good to everybody that it was easy to overlook that the value of the underlying assets existed in a speculative environment," said Alex Sheshunoff, a bank consultant whose firm keeps track of the performance of every bank and thrift in the country. "Perhaps the lenders didn't do the thorough investigation of his cash flow, when his net worth appeared to be so substantial."

While Trump's name was magic on his way up, it may turn out to be something of a curse now that his empire is beginning to show signs of unraveling. When he was in a buying mode, word that Trump was in the market for land or casinos or an airline by itself could boost the prices being asked and paid.

And now that he may be forced to sell into a market that is already soft, news of Trump's distress could send prices down further, according to real estate executives and other dealmakers.

"This is terrible for New York," said Phil Pilevsky, a major New York developer. "If something happens to Donald Trump, it will put a damper on development around the city. Perception is really important in this business, particularly to the banks." Pilevsky said he has been talking to many of the major banks and they are in "a frenzy over Trump," making it harder for all developers to borrow money.

Whether because he paid too much for his properties, as many said when they were bought, or because the markets for those properties have since declined, Trump now faces the prospect of taking losses on many of the assets he might want to sell.

Trump has invested as much as $75 million to refurbish planes and terminals since paying $365 million last year to buy Eastern Airlines's Washington-New York-Boston shuttle. At the time, Trump said he would make the shuttle a "diamond, an absolute diamond." But analysts now estimate that Trump stands to lose about $100 million if he can find a buyer, as his bankers are pressing him to do. It doesn't help Trump that Pan Am is also trying to sell its competing shuttle at the same time.

On the old West Side rail yards, Trump had hoped to build a collection of offices, condominiums and shopping centers known as Trump City, at an estimated cost of $4 billion. But today, while Trump City remains on the drawing boards, the interest and tax expenses on the land purchases alone are costing Trump about $25 million a year. Real estate executives say there is little chance that anybody would pay anywhere near enough to enable him to pay off the $200 million mortgage that Chase Manhattan Corp. holds on the property.

Trump was so successful at peddling the idea that he was a business genius that evidence of his business missteps has come as a shock. Bankers from three of the four major bank lenders to Trump said that the most startling aspect of the past three weeks of intense negotiations has been their discovery that Trump does not run a tight ship.

"His attention to expenses is certainly not what it should have been. That's rapidly becoming apparent," said one banker at a major New York bank with large loans to Trump. "But paradoxically, if there's a bright side to this -- and there is a bright side to this -- it's that he is able to tighten up, to cut expenses" and alleviate at least some of his cash-flow shortage right away.

Payrolls have already been trimmed at the Taj Mahal casino, and at the shuttle, where amenities have been curtailed and a cutback in weekend service is under consideration. Bankers are also pushing for cuts in advertising and promotion at the Trump Organization.

Several bankers with loans to Trump acknowledge that they too failed to pay attention to basics -- both in assessing the purchase price of properties and overseeing continuing operations. "Whether everything is as buttoned-up or as secure as the surface bravado indicated is now in question," said one.

Some real estate operators have long been aware of Trump's propensity to burnish his name at the expense of profits. The advertising and other marketing expenses for Trump Plaza, a condominium development in Palm Beach, for example, have nearly equaled the project's revenue, according to a prominent manager of distressed real estate who examined the property's financial statements two years ago.

"I was shocked to see the imbalance. ... It appeared Trump was more interested in advertising the Trump name than the project," he said. He said the numbers were out of whack even after taking into account that Trump had only owned the property for about a year at the time and, thus, might have been expected to have higher-than-normal marketing costs.

Another questionable business decision was the opening in April of the Taj Mahal casino, which must rake in more than $1 million a day in winnings to cover its expenses and debt payments. The Taj has met that target so far, but business is likely to fall off when the weather gets chilly in the autumn and the hype over the opening is forgotten, analysts said. Moreover, the Taj has gained some of its business at the expense of Trump's other two Atlantic City casinos, the Castle and the Plaza.

"Was it smart to build and compete against yourself with the Taj Mahal? I don't think so," said Benjamin Schore, a professor and head of the real estate program at Columbia University's Graduate School of Business. "I think he thought he was going to lock out his {outside} competition in Atlantic City forever. ... Is he going to be able to lock out his competition? Absolutely not, and there's a perfect example of arrogance," Schore said.

Ed Tracy, president of Trump's three casinos, said yesterday that the Taj Mahal planned to reduce its workforce from 6,500 to as few as 6,100 full-time jobs by summer's end. But he stressed that this was the normal practice for a newly opened casino, which needs fewer employees following its "shakedown" period. He predicted that Trump's three casinos would produce "an avalanche of cash" this year.

Trump has always taken care to put the best spin on his business activities, even when it involves telling less than the whole truth. When news that Trump's cash problems first began to surface earlier this spring, Trump dismissed it as malicious gossip. Days later, he acknowledged that he had explored selling a number of his properties, but explained it was a strategic move to make himself "king of cash." His aim, he said, was to be in position to buy up property once values had declined.

In financial statments filed with the Securities and Exchange Commission at about the same time, however, he was telling a different story about at least one property, the Trump Castle casino. In those filings, he reported that for the first three months of 1990, cash income from the casino had improved "somewhat" from the same period in 1989, but that "management believes that future cash flows may be further impacted" by the opening of the Taj in April.

"He tries to turn the public relations to make him look like a genius. He made it seem, I'm going to sell at a top, cash is king. If that was true, why wasn't he selling in 1987 and 1988, when the New York real estate market was booming away?" Jordan E. Goodman, a senior reporter at Money magazine who has covered Trump for several years, said.

Goodman was hardly the first to warn of the dangers of letting hype get in the way of sound business judgment.

"You can't con people, at least not for long," a New York dealmaker advised not long ago. "You can create excitement, you can do wonderful promotion and get all kinds of press, and you can throw in a little hyperbole. But if you don't deliver the goods, people will eventually catch on."

So wrote Donald J. Trump, in his best-selling book, "Trump: The Art of the Deal."