The savings industry, warning of "imminent crisis," yesterday proposed a multi-billion-dollar government aid package intended to ensure the industry's survival and to stimulate the housing market.

The three-year program would cost $10 billion the first year and less in succeeding years if interest rates drop.

Should the plan be passed by Congress, it would be by far the largest federal bailout in modern times. Lockheed Aircraft Corp. received $250 million in loan guarantees; Chrysler Corp., $1.5 billion; and New York City, a $4.5 billion long-term financing package.

Last year, savings and loan associations had operating losses of $4.9 billion and mutual savings banks lost $1.5 billion. The losses were primarily caused by high interest rates, which force thrift institutions to pay higher rates on their deposits than they receive on their old mortgage loans.

"As a result, our institutions are suffering massive operating losses and rapidly shrinking net worth positions reserves . Unless corrective action is taken by the Congress, confidence in the entire financial system could be undermined," declared Robert R. Masterton, chairman of the National Association of Mutual Savings Banks.

Saying "we can wait no longer for interest rates to fall," Roy G. Green, chairman of the U.S. League of Savings Associations, and Masterton yesterday jointly announced a three-part program consisting of capital maintenance, warehousing of low-yield mortgages and loan subsidies to home buyers. This was presented as a comprehensive solution, as contrasted to piecemeal rescue efforts that have been made on Capitol Hill.

Green said the league's economists have calculated that the proposed federal assistance ultimately would cost the government less than the current system of merging troubled thrifts, which they estimate will cost over $10 billion in the next three years.

Without assistance, Brookings Institution projects that 1,000 savings and loans, or about a quarter of the industry, will disappear in the next two years. The trade associations' program would preserve most of them.

The capital maintenance plan would pump enough funds--in the form of promissory notes guaranteed by the U.S. Treasury--into thrift institutions to maintain their net worth at 1.5 percent. (Current law puts the minimum at 3 percent, but substantial numbers of thrifts are below the minimum and some are even at zero net worth.) No cash would be exchanged except in the event of liquidation of a savings institution.

Portfolio assistance, or "warehousing" by the government of low yielding mortgages, is the core of the trade associations' program, accounting for three quarters of the first year's expenditures.

Any depository institution with more than 20 percent of its assets in fixed-rate residential mortgages would receive an interest rate subsidy on loans yielding less than 9 percent. (This would include virtually all thrifts.)

The subsidy would equal half the difference between the mortgage's rate and the average on 30-month Treasury securities. If, for example, the mortgage were 8 percent and the T-bill 14 percent, the thrift would receive in the form of a debenture a government supplement of 3 percent, bringing its yield up to 11 percent. The debentures would be traded back to the government after three years. The first year federal cash outlay would be $7.5 billion.

Finally, people who bought homes after the proposal went into effect would have their mortgage rates lowered by 4 percentage points for three years. The government would "buy down" the rate by three points, and the S&L or savings bank would contribute the other point. That would reduce current 16.5 percent mortgage rates to 12.5 percent.

According to the trade associations, the program, which would cost $5 billion over three years, would make $83.5 billion in additional home mortgage lending possible in the first year, or 1.6 million home sales.

A new independent federal agency would be set up to administer this program.

In a related matter, officials of the administration and the Federal Reserve expressed opposing views yesterday on whether new rules are needed for money market mutual funds. Fed Governor Lyle E. Gramley said that, although the funds have not yet created a serious problem for the Fed in controlling the money supply, the potential is there.

He urged that reserve requirements be established for the transaction portion of money market funds. Such a move effectively would lower the amount of interest paid on those funds that permit check writing.

On the other hand, Beryl W. Sprinkel, Treasury undersecretary for monetary policy, opposed changing Fed regulations to compensate for the effects of financial innovations like money market funds.