5R55W Transmission Solenoid Block Pack, 9L2Z-7G391-AA

This is the updated-design solenoid block pack for the Ford 5R55W and 5R55S five-speed automatics. It replaces Ford 9L2Z-7G391-AA, 9L2Z-7G234-AA and 4L2Z-7G234-AA, plus aftermarket numbers 58879WD and D46420B. The block bolts to the valve body and carries the shift, pressure control and TCC solenoids as one unit.

Applications: 2002-up Explorer, Sport Trac and Mountaineer 4.0L and 4.6L, 2003-2006 Aviator 4.6L, 2005-2010 Mustang 4.0L and 4.6L, and 2003-2006 Lincoln LS 3.0L and 3.9L.

The 5R55 solenoid block is a known weak point. Typical symptoms: harsh 1-2 or 2-3 shifts, a bang into 3rd, flaring between gears, no overdrive, or the transmission going into failsafe with shift solenoid or pressure control DTCs. The updated block addresses the original design's internal wear and sticking that caused these complaints. If the fluid is burned and clutches are worn, a new block will not fix a slipping unit, so check the fluid and pan debris first.

On the bench: drop the pan and filter, unplug the harness connector, remove the block bolts, and lift the old block off the valve body. Install the new block, torque the bolts to spec in sequence, reconnect the harness, refill, and run a relearn or drive cycle so the TCM adapts.