The union also reached a separate tentative deal with Delphi Automotive Systems Corp., the former GM parts unit which was spun off as an independent company earlier this year.

The pacts came after about 37 hours of nonstop negotiations and direct talks between UAW president Stephen Yokich and GM chief executive officer Jack Smith.

The parties declined to release details of the deals, but they were expected to mirror the terms of a four-year contract the UAW reached with DaimlerChrysler AG on September 16.

That deal, ratified by 86 percent of the automaker's union members over the weekend, included 3 percent wage gains in each of the contract's four years, a $1,350 signing bonus and higher pensions.

The tentative contracts cover about 172,000 hourly workers at GM and 48,000 at Delphi, according tofigures provided by the UAW.

The UAW-GM pact, following months of secretive talks before negotiations accelerated Monday, comes just over a year after nearly two-month long strikes at two Flint, Mich. plants cost the automaker $2 billion.

Following the Flint strikes, the two sides took steps to mend their traditionally rocky relations, culminating with Tuesday's tentative contract agreement.

Local union leaders from GM plants are expected to vote on the tentative pact on Friday in Detroit, industry sources said. If approved at that forum, the agreement goes to rank and file union members from across the country for a tentative vote at a later date.

Wall Street analysts considered the economic aspects of the pact affordable for GM. But the automaker had to struggle with job security provision as outlined in the DaimlerChrysler pact, which required the company to replace workers who leave with new hires when employment falls below a certain level.

GM, the highest-cost U.S. automaker, needs to trim itshourly work force by tens of thousands to match the efficiencies of its competitors.

The deals with DaimlerChrysler and GM help ensure that this year's record-setting U.S. sales will continue without any labour disruptions. However, some of the thorniest issues have yet to be resolved at Ford Motor Co.

Ford and the UAW are expected to clash over a provision of the DaimlerChrysler pact that bans the sale, closure or spinoff of plants. The No. 2 automaker has said it wants more independence for its Visteon parts subsidiary and may spin off or sell the operation.

The UAW is opposed to separating Visteon because it could threaten the wages and job security of the 23,500 UAW members who work in Visteon plants.

Because the Visteon issue is regarded as one of the most difficult the union faces in the new contract, it has put Ford last in the order.

Meantime, the Canadian Auto Workers Union began negotiations with DaimlerChrysler for a new contract covering 14,000 workers. CAW workers have already approveda new three-year contract with Ford. The CAW-Ford deal includes an inflation-adjusted 4.5 percent wage increase in each year and a C$1,000 signing bonus.