General Motors Co. and the United Auto Workers are moving toward a tentative agreement that would put an end to a major strike that’s dragged on for more than a month, according a top union negotiator.

“All the pieces are there, we just have to glue it together,” said Mike Booth, vice president of the union’s GM department, on the sidelines of a labor rally in downtown Detroit Thursday.

GM, along with rivals Ford Motor Co. and Stellantis NV, has been trying to cut a deal to end a walkout that started Sept. 15. All three companies have offered UAW workers historic wage increases and the reinstatement of inflation protection measures the union gave up during the financial crisis.

Booth said the sides are getting closer but haven’t yet come to an agreement on pay and pensions. GM has offered 20% raises over four years, while rival Ford has offered 23%. The UAW believes “20% is not enough,” according to Booth.

A GM spokesperson declined to comment.

The UAW has been walking out of select plants and has said it will add facilities if talks don’t progress. Workers at a GM pickup plant in Missouri are on strike along with 18 parts-distribution warehouses. The union was going to strike the company’s large-SUV plant in Arlington, Texas, but decided against it at the last minute when the carmaker agreed to recognize future hires at electric-vehicle battery plants as part of its master labor agreement.

The company and union are also hashing out pensions and health care for retired workers. Booth said the union wants a guaranteed pension, but that it’s open to negotiate as long as a strong plan to protect members is in place.

“There’s a possibility of people retiring very comfortably with a defined contribution plan,” he said.

Booth said the union met Thursday with GM negotiators, including Chief Executive Officer Mary Barra, and gave the company a comprehensive proposal. The two sides will meet again Friday to continue talks.

(Updates with GM no comment in fifth paragraph.)