Chrysler Corp. workers, anxious to receive the same benefits that General Motors Corp. and Ford Motor Co. workers received in new contracts last fall, are preparing contract demands for talks beginning April 18. Members of the United Auto Workers union's 140-member national Chrysler council were to begin arriving in Kansas City, Mo., today for a meeting with national UAW leaders and elected union bargainers. By Friday, the council planned to have discussed and approved demands that will guide how the industry pattern contract, established at the two larger companies, can be installed at the smallest Big Three automaker. The Chrysler contract, covering 59,500 active and 8,000 laid-off workers, expires Sept. 14. Talks are scheduled to begin April 18, instead of mid-July as usual. The two sides agreed to early talks to stem damage inflicted by friction over Chrysler's closing of an assembly plant in Kenosha, Wis., and the abortive sale of its 28,000-worker Acustar Inc. parts subsidiary. Chrysler was stunned by the speed and severity of the union's opposition to the proposed Acustar sale. Angry workers at locals across the nation began preparing ``strike packages'' _ lists of grievances over locally strikeable issues _ and stopped cooperating in crucial management-union programs aimed at improving quality and production efficiency. UAW Vice President Marc Stepp, who will lead negotiations with Chrysler, told workers at the time that he would give local unions with grievances permission to strike immediately. A few strikes at key assembly and parts plants could have crippled Chrysler as quickly as a national strike. Chrysler quickly backed down from the proposed sale in early March and agreed to early contract talks, a request it had refused last fall after the union wrapped up contracts at Ford and GM. Negotiators on both sides are limited to working within the pattern contract, which forbids layoffs except during declining sales of a particular product and requires automakers to continue paying workers whose jobs are lost to productivity improvements, new technology or transfer of work to outside suppliers. The pattern contract also includes joint six-month, plant-by-plant studies that will examine ways to strengthen operations and keep work inside each company. The UAW hopes the studies will make it harder for automakers to pit plant against plant in competition for a shrinking number of jobs. The UAW is expected to seek a two-year contract instead of the usual three-year pact so that its contracts with all Big Three makers will expire together in 1990. The union also will seek more representation on the Chrysler board of directors. UAW President Owen Bieber has a board seat, but the union believes holding more seats will give it more control over Chrysler decisions. Bargainers will work against an artificial target deadline instead of a strike deadline, so Chrysler faces no risk of a companywide strike if talks fail. Industry analysts expect a quick settlement. But a failure at the table would sour relations and make talks more difficult when the two sides were forced to resume bargaining in the summer.