A bad batch of transmission fluid could end up costing Ford Motor Co. a lot of money and more unwanted negative publicity concerning vehicle quality.

The auto maker will notify some 740,000 Ford Explorer SUV, Ranger pickup, Mercury Mountaineer SUV and Lincoln LS sedan owners there is a potential problem with the vehicle’s 5-speed 5R55 or 5R44 automatic transmission.

Explorer headlines Ford’s latest recall.

Ford is terming the recall a “customer service program,” a spokeswoman says, and the recall only affects ’04 vehicles in North America.

The auto maker also will recall vehicles in other countries equipped with the affected transmission, including Australia, where potentially defective Explorers have been sold during the ’04 and early ’05 model years, according to internal reports available on the Internet.

The SUVs represent the bulk of the problem vehicles, the spokeswoman says, although it is unknown exactly how many are affected. All likely affected vehicles were assembled in North America.

The transmissions in question were sourced from Ford’s Bordeaux transmission plant in France prior to May 10, 2004, a Ford service technician tells Ward’s. The transmissions were filled with improper-specification Mercon V fluid, which causes one of the solenoids to swell, he says.

Ford will not disclose the supplier of the transmission fluid.

The transmission is plagued by a potential delay between park and the reverse gear, the spokeswoman says. The delay is accompanied by a banging sound, but does not present a safety risk, she insists.

The problem, which has been on Ford’s radar screen since at least June according to corporate communication with dealers, was brought under a significant microscope following a recent report by the WCBS television news station in New York. While the station takes credit for pushing Ford to action, the Ford spokeswoman says the company already was investigating a cure and considering a customer notification program.

The procedure to fix the issue takes about four hours, involves reprogramming the powertrain control unit and usually is covered under warranty as the vehicles tend to be less than a year old. Ford is devising a service procedure that will cut the service time and include draining the transmission fluid and replacing the swollen solenoid, the spokeswoman says.

A dealer service technician in Pennsylvania says he has fixed about six affected vehicles per month, and others in the shop have done similar repairs.