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Okay so in an effort to dispel confusion and misinformation, I decided to make a user-friendly guide to 4f27e shift solenoids. im using these docs as my sources
http://www.atsgmiami.com/articles/html/4F27E Shift Strategy/4F27E Shift Strategy.htm
http://www.zoom-tech.com/downloads/support/tranxpages/ford/4f27e.pdf
Shift solenoid A:
This solenoid appears to ONLY control 3-4 shifts.
Shift solenoid B:
This solenoid only controls torque converter lockup. When this solenoid is activated, The clutch inside the torque converter locks the stator to the impeller, making it a mechanical connection rather than a fluid one. Improves engine efficiency, and also drops the rpm by 200-300.
Shift solenoid C:
This is the big mamma. This solenoid controls the forward clutch for each shift. It is a pulsewidth-modulated solenoid, meaning the time length of a shift can be changed via an ECU tune. If this solenoid goes bad, you will have issues with the rpm jumping up really high during shifts and the trans will hesitiate to go into gear.
Shift solenoid D:
This solenoid controls whether or not first gear is engaged. When it is activated, it empties an accumulator filled with fluid, which releases a spring that engages 1st gear. This is why 2->1 downshifts are relatively rough. This solenoid also opens the 2nd/4th band of clutches when 1st is engaged. If this solenoid goes out, you may experience bucking when starting from a stop, or troubles downshifting into first.
Shift solenoid E:
im having a hard time figuring out what this one does, but it appears to only control 2-3 shifts.
EPC solenoid:
This solenoid controls how much pressure is in the solenoid system. It is told how much to give by the throttle position sensor. More throttle = more pressure.
obviously im just an amateur... just hope this will help someone out when we say "Shift solenoids are going out"
http://www.atsgmiami.com/articles/html/4F27E Shift Strategy/4F27E Shift Strategy.htm
http://www.zoom-tech.com/downloads/support/tranxpages/ford/4f27e.pdf
Shift solenoid A:
This solenoid appears to ONLY control 3-4 shifts.
Shift solenoid B:
This solenoid only controls torque converter lockup. When this solenoid is activated, The clutch inside the torque converter locks the stator to the impeller, making it a mechanical connection rather than a fluid one. Improves engine efficiency, and also drops the rpm by 200-300.
Shift solenoid C:
This is the big mamma. This solenoid controls the forward clutch for each shift. It is a pulsewidth-modulated solenoid, meaning the time length of a shift can be changed via an ECU tune. If this solenoid goes bad, you will have issues with the rpm jumping up really high during shifts and the trans will hesitiate to go into gear.
Shift solenoid D:
This solenoid controls whether or not first gear is engaged. When it is activated, it empties an accumulator filled with fluid, which releases a spring that engages 1st gear. This is why 2->1 downshifts are relatively rough. This solenoid also opens the 2nd/4th band of clutches when 1st is engaged. If this solenoid goes out, you may experience bucking when starting from a stop, or troubles downshifting into first.
Shift solenoid E:
im having a hard time figuring out what this one does, but it appears to only control 2-3 shifts.
EPC solenoid:
This solenoid controls how much pressure is in the solenoid system. It is told how much to give by the throttle position sensor. More throttle = more pressure.
obviously im just an amateur... just hope this will help someone out when we say "Shift solenoids are going out"