G.M. already makes many of its own parts, and so has fewer opportunities to move into new parts operations at lower wages.

Profits of parts operations are usually not reported separately.

G.M. also will pay for buyouts of 13,000 workers at the Delphi Corporation, its former parts operation.

Under the letter, Transcisco was to acquire certain parts operations of Piper.

Angry union officials charge that the company is trying to shed the parts operations before bargaining for a new labor contract this fall.

Inchcape also runs AutoNexus, a parts operation.

Some of them had previously indicated, however, that a public stock offering -although a possibility in the future -was not an immediate prospect for the parts operation.

ITT has sought automotive parts operations to add to its growing automotive business, which recorded about $3.5 billion in sales in 1992.

G.M. is selling 80 percent of its $760 million parts operation to ITT for $400 million.

The European parts operation is supplemented and supported by those in Asia and America.