Major banks have told Chrysler Corp. privately that they want to wipe out about half of their $1.2 billion in claims against the auto company by taking an accelerated cash payment for a fraction of the debt and severing their remaining ties with Chrysler, according to informed sources.

The proposal, made in the midst of critical, sensitive negotiations over Chrysler's future, is subject to different interpretations. It could be a plus for Chrysler, substantially reducing its debt and interest expense. Or it could indicate that the banks no longer believe in Chrysler's long-term chances and want to cut their losses as soon as possible, said sources close to the negotiations.

Under the proposal, which still was being worked on yesterday, the banks would settle for perhaps as little as 15 to 20 cents on the dollar on roughly $600 million in loans to Chrysler, but would expect prompt cash payment on a preferred basis. The money would come from this year's sales of Chrysler cars and trucks, rather than directly from the $400 million in guaranteed loans that the company hopes to obtain with the federal government's approval, according to informed sources.

Chrysler has proposed its own plan for disposing of the remainder of the debt by asking creditors to accept $573 million worth of preferred Chrysler stock for their outstanding notes. Because Chrysler stock has little value, creditors who accept this plan in effect are writing off that portion of their claims against Chrysler, financial analysts said.

The proposed arrangements with the banks would be a distinct plus for Chrysler if it wins the $400 million in loan guarantees and sees its sales grow this year. Its hopes for 1981 have improved recently with the success of its current rebate plan tied to the prime interest rates. "The company can generate cash quickly if the cars are moving," said one source. At an average price of $6,000 a car, a gain of 25,000 cars sold a month would produce $150 million in sales revenue out of which to pay the banks, this source noted, adding that this kind of improvement is possible this spring.

The proposal by the banks indicates, however, that they now are reluctant to bet on that recovery, other sources said.

As these negotiations between Chrysler and its banks continued, the company also was meeting with top United Auto Workers union negotiators, seeking $673 million in wage concessions over the next 21 months. The company's proposal would freeze pay and benefits for Chrysler's 90,000 UAW workers.

The arrangement with the banks and the wage concessions are part of a new Chrysler financial plan that is meant to cut costs by $1 billion this year and a total of $2 billion by 1985. Without these savings, the loan board says it will not approve the $400 million in loan guarantees.

UAW President Douglas Fraser said yesterday the union has offered to make new, undisclosed financial concessions to Chrysler in an effort to win approval of the $400 million loan guarantee. The UAW and Chrysler moved negotiations on the current wage contract to Washington yesterday to permit closer contact with Treasury Secretary G. William Miller, chairman of the loan board.

Fraser met yesterday morning with Miller and said the Treasury secretary is "still hopeful" that the loan board can grant at least a preliminary approval on Wednesday. For that to happen, however, the company must be in agreement with the UAW, the banks and its suppliers on the package of financial concessions.

Miller reportedly is pushing hard to put the loan board on record in favor of the $400 million loan guarantee installment before he leaves office Jan. 20 with the Carter administration. Under the Chrysler loan act, Congress is given 15 days to review loan board decisions, putting the final decision on Chrysler's current request into the hands of the incoming Reagan administration. But Chrysler officials believe a preliminary approval now would significantly improve their chances of a favorable final decision after Jan. 20.