DETROIT (AP) _ Labor discontent still simmering beneath the surface at Chrysler Corp. isn't likely to prevent the No. 3 automaker and the United Auto Workers from reaching an early contract settlement by summer, observers say.

Since Chrysler backed down in early March from the planned sale of its 28,000-worker Acustar Inc. parts subsidiary, caustic rhetoric and the threat of crippling strikes have been replaced by the silence of negotiators preparing demands and strategies for the planned opening of talks April 18.

The union's demands will be discussed and approved by the 140-member UAW national Chrysler council during a meeting in the coming week in Kansas City, Mo.

The talks and the settlement to which they lead are likely to be much less dramatic than the unrest that led to Chrysler's agreement to negotiate early, since the contract must follow an industry pattern established last fall at Ford Motor Co. and used at General Motors Corp.

''The framework should be there, and the readiness to bargain early should generally be an admission that things will go smoothly,'' said Harley Shaiken, labor and technology expert at the University of California at San Diego.

However, Shaiken added: ''Given all the trauma (at Chrysler) in recent years, there could be a surprise. There is discontent in Chrysler plants, a real unease that could come out in this bargaining.''

Chrysler's contract covering 59,500 active workers and 8,000 on layoff expires Sept. 14. The UAW wanted to adapt the three-year Ford and GM contracts to Chrysler last fall. Chrysler, however, didn't agree until it backed off from the Acustar sale, realizing it had opened a wound that would only fester if left until the normal mid-July opening of talks.

The majority of Chrysler's workers were there during the brush with bankruptcy in the early 1980s and gave concessions to help the company survive. Many say they are disillusioned because a spirit of camaraderie, of fighting together, has disappeared now that Chrysler is in the black and their contributions aren't so keenly needed or appreciated.

''The average auto worker at Chrysler in 1979-81 had no business assuming they were going to have a job there. But they made it through beautifully, the company's done very well. To now have to start worrying about your job is very nerve-wracking,'' said Michael Luckey, an independent auto industry analyst who has worked closely with Chrysler.

Chrysler workers have reasons to worry, analysts agreed. Chrysler appears to want to close at least one assembly plant not previously announced and possibly more than the six announced Acustar plants planned for closing the next two years.

Chrysler also will maintain heavy pressure to produce the most products with the fewest workers possible, said Chris Cedergren, industry analyst with J.D. Power and Associates in Agoura Hills, Calif.

''Chrysler's success in the past five or six years has been driven by their ability to really go out and cut costs dramatically. Their success in the future will be driven by their ability to continue being the low-cost producer'' among the Big Three, Cedergren said.

While vital to all automakers, cost-cutting is crucial at Chrysler because its sales depend on keeping its prices lower than GM and Ford, Cedergren said.

Negotiators' main task will be to fit the pattern set at the two large companies to the smallest of the Big Three. The sooner they finish, the sooner Chrysler workers will share protections that cover Ford and GM workers:

-A ban on plant closings.

-Job security provisions that forbid layoffs unless sales of a particular product fall, restrict transfer of inside work to outside suppliers and put workers who otherwise would be laid off because of outsourcing or improvements in technology or efficiency into a job bank where they receive most of their regular pay and often retraining.

-An agreement for the two sides to study jointly over six months ways to improve quality and productivity at each plant.

Among potential obstacles to a quick and eventually healing settlement is what many view as a loophole in the pattern contract.

Although the contract forbids plant closings, GM has skirted that obstacle by simply laying off all the workers at a plant whose product isn't selling well and indefinitely idling the factory. The idling of a factory in Framingham, Mass., was temporary, but two other closings announced since the contract was signed - at Kansas City, Mo., and Pontiac, Mich. - are likely to be permanent.

In the Chrysler talks, UAW negotiators are expected to seek a tighter definition of indefinite idling, a difficult task and one likely to be resisted by Chrysler, Shaiken said.

''It would be difficult to renegotiate the Ford and GM contracts at Chrysler,'' he said.

End Adv AMs Monday April 4