Fiat Chrysler (FCAU) - Get Report and the United Auto Workers union on Saturday said they have reached a tentative deal on a new labor contract - the last of what used to be known as the "Big Three" automakers to do so.

In a statement, the UAW Bargaining Committee on Saturday said it had agreed to a deal with Fiat Chrysler to add $4.5 billion in investments, equaling roughly 7,900 jobs over the course of four years.

The $4.5 billion comes on top of an earlier pledge of $4.5 billion for a total of $9 billion marked for new investment, UAW Vice President Cindy Estrada said in the statement. 

The agreement follows the recent resignations of two top union officials including UAW President Gary Jones, who has been connected to an ongoing federal corruption probe of the union.

Jones, whose Michigan home was raided by federal agents in August, has not been charged by federal prosecutors.

The UAW-Fiat Chrysler National Council will meet on Dec. 4 to review the proposed deal. If adopted, the tentative agreement will go to all Fiat Chrysler hourly and salary workers for a ratification vote that will begin on Dec. 6.

The UAW earlier this fall secured a four-year labor contract with General Motors (GM) - Get Report after a 40-day strike that cost the automaker as much as $4 billion for the year and $1 billion in the third quarter.

That preceded a much quicker round of negotiations with Ford (F) - Get Report , with the union also securing an agreement in mid-November.