GUANGZHOU, China — General Motors has reached a preliminary agreement for the sale of its Hummer brand of large sport utility vehicles and pickup trucks to a machinery company in western China with ambitions to become a carmaker, a person familiar with the Chinese government approval process said Tuesday.

The Sichuan Tengzhong Heavy Industrial Machinery Company Ltd., based in Chengdu, concluded the agreement with G.M., said the person, who insisted on anonymity.

Sichuan Tengzhong is a privately owned company, but Tuesday’s deal required preliminary vetting by Beijing officials, who retain the right to veto any attempt at an overseas acquisition by a Chinese company and who give special attention to deals over $100 million.

G.M. announced the deal early Tuesday morning in Detroit but said that the memorandum of understanding would not allow it to reveal the buyer or the price. Industry analysts have estimated that the Hummer division would sell for less than $500 million.

Sichuan Tengzhong is known in China for making a wide range of road equipment, from bridge piers to highway construction and maintenance machinery. But even before the Hummer deal, the company has been moving more into heavy-duty trucks, including tow trucks and oil tankers.