The union that represents Ford Motor’s Canadian manufacturing workers reached a tentative contract agreement on Tuesday, averting a strike but setting up what may be a difficult campaign to get the deal approved by members.

The union, Unifor, said Ford f would make investments in its Canadian operations in the area of C$700 million ($522 million) under the agreement, and promised other undisclosed gains for members.

But the deal maintained a 10-year wage progression for new hires that is unpopular with some workers at Ford‘s Oakville assembly, and followed a pattern set in negotiations with General Motors in offering new hires a defined contribution pension plan.

It was not immediately clear whether the deal would be approved at ratification meetings on Nov. 5 and 6.

“There’s things in this agreement that we don’t like, and there’s things in every agreement that we have bargained that we don’t like,” said Bob Scott, vice chair of the bargaining committee, who also represents Oakville workers. “I believe that our members are going to be quite happy.”

In a public letter and interview in early October, the president of the Oakville local, Dave Thomas, said a deal similar to the one approved at GM would likely be rejected in Oakville, where 5,000 of the union’s nearly 7,000 Ford employees work.

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Some 2,200 of Oakville’s workers are recent hires, and many had hoped the 10-year earn-in, which keeps their wages below more experienced peers, would be shortened in the new contract. Instead, the deal signed at GM gm and Fiat Chrysler Automobiles NV fcau shifted some raises earlier in the 10-year progression, and offered $12,000 in bonuses over four years.

The union practices pattern bargaining, selecting one of the three automakers to lead negotiations and then insisting its rivals agree to similar deals.

The bargaining committee had vowed to win new investment for Ford‘s Windsor engine plants. National President Jerry Dias said one of those plants, Essex, would get a major new engine program, and a separate Windsor site would continue producing 6.8 liter engines through the end of the four year agreement.

Dias said the contract offered Ford workers gains “over and above” the pattern set at GM, but declined to give details.

He said Ford had agreed to make the Oakville assembly the “primary supplier” of its models for export internationally.

In a release, Ford said it had reached a deal but would not discuss specifics.