Auto companies began curtailing operations yesterday as a Teamsters union strike resulting trucking industry lockout sent their first tremors through the American economy.

There were conflicting claims about the initial impact, and the government continued to take a wait-and-see attitude about seeking a court injunction to force a resumption of normal trucking service.

Industry officials claimed that shutdown was "virtually 100 percent effective" among the 500 firms that account for 80 to 85 percent of the unionized interstate freight business.

But Teamsters President Frank Fitzsimmons accused the industry of the industry of vastly exaggerating the impact of the industry lockout to provoke President Carter into seeking a back-to-work injunction.

Fitzsimmons also told a news conference that 300 to 400 trucking firms have indicated a willingness to negotiate with the union independently of Trucking Management Inc. (TMI), the industry bargaining group that called the lockout.

He said these firms, which he did not identify or characterize as to size, are "signing contracts with the union based on the union's last proposal," which included money and work-rule demands that TMI rejected when industrywide bargaining broke down late Saturday.

The Teamsters called selective strikes early Sunday when its master freight agreement covering 300,000 drivers an warehouse workers expired without a new agreement. TMI retaliated later in the day with a "defensive bargainers said their last offer, rejected by the union, included a 30-plus percent increase in wages and benefits over three years. Although industry officials characterized this as within the Carter Administration's much-relaxed 7 percent-a-year wage guideline, the union's rejection of it was viewed as a possibly fatal blow to the already faltering program because unions such as the Teamsters rarely strike without getting more money in the end.

In his remarks yesterday, Fitzsimmons renewed its criticism of presidential inflation advisers, saying they shared blame for the strike and lockout.

He also discussed the Teamsters' strategy for coping with a possible government request for an injunction, indicating the union would seek to limit any injunction to the lockout, thus permitting a continuation of the union's selective, or targeted, strike against 73 individual companies.

An injunction under the Taft-harley Act requires that the national health or safety be imperiled, and the union would argue that the limited strikes do not do this, while the lockout does.

The lockout's immediate fallout on the auto industry was expected because of car companies' dependence on truck shipments of parts. General Motors and Ford, the two largest U.S. automakers, put more than 60,000 assembly-line workers in a dozen plants on short shifts yesterday and said further cutbacks were imminent.

Interstate Commerce Commission officials said it appeared that all major trucking firms outside of the sparsely unionized South were shut down yesterday. However food shipments were generally continuing for the time being, although Boston reported that food deliveries to public schools had been interrupted.

No further negotiations are scheduled, although a resumption is considered likely after a meeting of the union's 350-member negotiation committee in Chicago tomorrow.

Local impact of the lockout appeared to be minimal yesterday. Spokesmen for Giant and Safeway food stores said deliveries were being made as usual to their Landover warehouses.

At Smith's Transfer Corp. in Alexandria, a firm locally targeted by the Teamsters, manager John Davis said shipments already delivered to the warehouse were being picked up but no new ones were coming in.