Problems With the Mercury Transmission Solenoid

by Horacio Garcia
Modern leather interior of the new car image by terex from

The transmission solenoid controls the flow of transmission fluid throughout the transmission of a Mercury automobile. Many technical service bulletins (TSB) and consumer reports cite problems with the solenoid in some Mercury models such as the Sable, Grand Marquis, Mountaineer or Cougar.

Loss of Gears

A TSB is published on the 2000 Mercury Cougar concerning the intermittent loss of first and second gear because of a problem with the transmission solenoid. The transmission solenoid pack has several electronic solenoids that open and close the desired gear. The transmission solenoid is remaining closed for the first and second gear, preventing fluid from entering the gears when accelerating. This requires a complete transmission overhaul or replacement because the transmission solenoid is inside the transmission.

Transmission Control Module

The transmission control module (TCM) for the Mercury transmission has a TSB concerning a programming error causing problems with the transmission solenoid. The TCM sends signals to the solenoid pack and into the electronic transmission solenoids controlling whichever gear is being shifted. The programming error is causing the wrong signals to be sent to the electronic solenoids, and the Mercury transmission is shifting the wrong gears. The Mercury transmission begins to stall or jerk once this transmission solenoid problems occurs. The TCM needs to be reprogrammed to fix this solenoid problem.

Fluid Build-up

The Mercury transmission solenoid builds up fluid and causes the gears to jerk when shifting or hesitating during acceleration. This transmission solenoid problem is attributed to fluid seeping from the vents and into the solenoid pack, causing too much transmission fluid to enter the control solenoids. Once too much fluid builds up in the control solenoids of the transmission, the solenoids do not open and close properly. The gaskets on the transmission vents need to be replaced to correct this problem.

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