Transportation Secretary Drew Lewis moved yesterday to calm growing discontent among air traffic controllers who still haven't received the pay raises they were promised when they stayed on the job a year ago as their co-workers struck.

The controllers' $57 million raise is buried in the House Post Office and Civil Service Committee because of a dispute between the Reagan administration and the committee's chairman, Rep. William D. Ford (D-Mich.).

Lewis says Ford's conditions for releasing the money would force him to re-hire all of the 11,400 controllers President Reagan fired. Ford disputes that, saying his version would permit Lewis to hire enough of the fired controllers to quickly return the air traffic control system to full operations.

Lewis' calm-the-troops move came in a "Dear Colleague" letter signed by himself and Federal Aviation Administrator J. Lynn Helms. The letter, sent to all 10,200 working controllers, praised them for "dedication and devotion and said, "We are continuing to work to ensure that you are fully compensated for the job you do and that you receive the pay package you so richly deserve . . . ."

Many of the controllers who stayed have been forgoing vacations and working six-day weeks to keep the air traffic system at what the FAA says is 83 to 84 percent of its former capacity. Reports of restlessness among them are heard with increasing frequency as the pay bill languishes.

The administration bill would provide a 5 percent premium pay increase for all controllers, plus extra pay for activities such as training new controllers on the job. It passed both the Senate and House as part of the continuing resolution that Reagan vetoed late in 1981. When a subsequent version of the resolution was offered, Ford got the pay raise removed on procedural grounds.

A spokesman for Ford said yesterday that the congressman and "a majority of this committee have not felt that the administration's bill does anything to rebuild the system or to stabilize the system in the future." He pointed to Lewis' own study of air traffic control, which found that problems of management and personnel in the FAA went far beyond the question of money.

Ford has proposed that some of those who struck be rehired, and challenges Lewis' contention that, under civil service regulations, if any are rehired all would have to be.

"At this point, we don't need many of" the fired controllers, Lewis said yesterday. "If we could hire them back selectively, we would." Lewis said he hopes to be able to work out the problems with Ford.