The American Automotive Policy Council, which represents the interests of Ford, General Motors and Chrysler, while supporting the TPP in principle, also has attacked it because of the opening to Japan. "It is stunning that the U.S. government would endorse a trade policy that puts the industry at a competitive disadvantage and comes at the cost of American auto jobs," says Matt Blunt, AAPC president.

The AAPC, along with the Alliance for American Manufacturing and the American Iron and Steel Institute, on Thursday applauded a bipartisan letter signed by a majority of the House of Representatives calling on Obama to push for strong currency-manipulation rules in the TPP agreement.

The letter led by U.S. Reps. Rick Crawford (R-AR), John Dingell (D-MI), Sam Graves (R-MO) and Mike Michaud (D-ME), emphasizes how unfair currency policies distort trade, harming American workers, exports and economic growth. The TPP trade agreement needs to create a level playing field that will prevent further jobs from being shipped overseas as a result of currency manipulation, it says.

“Undervalued exchange rates allow other countries to boost exports of their products and to impede exports of ours,” the lawmakers wrote. “They also contribute to trade imbalances and market-access limitations that make it difficult for U.S. companies to compete in foreign countries.”

U.S. trade officials have said Japan has agreed to separate negotiations focused on regulatory and non-tariff barriers believed to keep U.S. vehicles out of the Japanese market, according to a Reuters report. And it agrees to a U.S. phase-out of its auto tariffs over the longest period possible under the future TPP deal.

The report also says Tokyo is promising to create a simpler and faster certification method used by U.S. auto makers to export to Japan, allowing up to 5,000 units of each vehicle type under the program, compared with 2,000 previously. But so far those assurances have not been enough to win over the opposition.

Against this backdrop, U.S. environmental and labor activists are trying to mobilize grass-roots opposition to the TPP. 

An analysis of the proposed text of the agreement, which leaked last summer, indicates major beneficiaries of the trade pact would be energy and pharmaceutical companies and financial institutions, which could free themselves from regulations, according to Lacey Kohlmoos, an analyst and organizer with the Washington-based Global Trade Watch, an offshoot of Ralph Nader's organization Public Citizen.

The proposed TTP agreement also could scuttle existing environmental, health, zoning and labor laws, she says.

The Sierra Club, a top environmental lobbying group agrees. "The TPP touches on a broad range of issues – environment, workers and jobs, access to medicine and more," the group says in a statement condemning the ongoing negotiations. "Despite the impact that the TPP would have on nearly every aspect of our lives, the TPP is being negotiated in near-complete secrecy."

The goal of the campaign being organized by Global Trade Watch and Public Citizen is to peel away support for the trade pact among Democratic congressmen and senators, Kohlmoos says during a recent visit to Detroit.

Despite Obama's support for the TPP, many Democrats in Congress have serious reservations about the proposed pact, she says, citing Sen. Sherrod Brown, (D-OH), who won re-election in 2012 with substantial help from the UAW. Many Republicans who support the idea of free trade also oppose the TPP, which Kohlmoos says is exceptionally complex.

"The TPP is NAFTA (North American Free Trade Agreement) on steroids,” she says. “It's designed to break down trade barriers at all costs. It has gone through 17 rounds of negotiations and it's getting broader all the time."

The Obama Admin. wants the TPP pact finalized by the end of the year, and Sen. Max Baucus, (D-MT), has said he plans to introduce a bill soon that would give the president "Fast Track" authority to finish the deal, meaning the agreement could not be amended or subject to a filibuster in the U.S. Senate.

Kohlmoos claims the U.S. has lost 5 million manufacturing jobs since NAFTA was signed in 1993, and more jobs will be lost if TPP is approved.

"I'm sorry we didn't block NAFTA," says Selwyn Rogers, a long-time UAW Local 160 member who met with Kohlmoos on her visit here. "We tried but failed. I feel (TTP) is even worse."