September 30, 2005
Ford 4R44E, 4R55E, 5R44E and 5R55E units often suffer shift abnormalities caused by excess wear in the solenoid regulator valve bore. This wear allows fluid loss which prevents proper regulation of oil pressure supplied to control solenoids, resulting in harsh or soft shifts, solenoid codes, wrong gear starts, TCC apply issues, and clutch failure. Reconditioning the bore and installing Sonnax oversized solenoid regulator valve kit 37947-48K re-establishes correct clearance for revived shift control in all ranges.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.