PEORIA, Ill. (AP) _ Caterpillar Tractor Co., citing seasonally low winter sales, Wednesday reported a $70 million loss for the first fiscal quarter, pushing the company's cumulative deficits since the start of 1982 to more than $1 billion.

The Peoria-based road construction-machinery builder said the loss came on sales of $1.48 billion during the first three months of this year.

Caterpillar said first-quarter sales improved by $90 million over the same period a year ago.

The world's leading heavy-equipment maker said the first-quarter loss compared to a $109 million deficit for the same period of 1984.

In its latest annual report, Caterpillar had predicted a first-quarter loss for 1985, but expressed confidence it could turn a profit for the full year.

Also Wednesday, Caterpillar stockholders, at their annual meeting in San Francisco, elected a new president to replace retiring Robert E. Gillmore.

Peter P. Donis, the company's executive vice president, will take over as chief operating officer June 1, the company said.

Gillmore, who has reached Caterpillar's mandatory retirement age of 65, will leave his post at the end of May, but will continue on the company's board of directors.

Earlier this year, Caterpillar got a new chairman of the board, George Schaefer, when former Chairman Lee Morgan retired.