A solenoid assembly for an automatic transmission of a motor vehicle. The solenoid assembly includes a housing, a valve, an armature and an electromagnetic device. The valve is mounted within the housing. The valve is operative in a vented state and a non-vented state and includes a plunger and ball combination movable between a first position for establishing the vented state and a second position for establishing the non-vented state. The armature is associated with the valve and is movable in response to the presence and absence of a magnetic field for selectively moving the plunger and ball combination between the first and second positions. The electromagnetic device is operative for creating the magnetic field. The electromagnetic device includes a core and an energizable coil. The core has an upwardly extending outer post with a generally rectangular cross section in a horizontal plane. The energizable coil defines an opening for receiving the first upwardly extending outer post. The core preferably includes a plurality of vertically stacked plates.