The coast clutch valve functions differently in 4R44E/55E units and 5R44E/55 units. The valve is the same but the porting used in their different separator plates makes the difference and will create different complaints as a result of valve or bore wear. In the 4R units, this valve is needed to get proper overdrive servo apply and bring on coast clutch. In the 5R units, the valve is needed to vent overdrive servo release oil and to bring on the coast clutch. Engine braking or loss of coast clutch are common complaints in either unit. Complaints of loss of 4th gear in a 4R or loss of 2nd or 5th gear in a 5R are associated with this valve. The Sonnax oversized coast clutch valve kit 37947-33K and tooling salvages the valve body and restores proper coast clutch function in either style unit.

• Oversized valve allows valve body to be refurbished and salvaged.
• Hard-coat anodized valve resists wear.
• Elongated front spool adds stability and prevents blow-by leakage.
• Annular groove centers the valve hydraulically to prevent wear.
• Recalibrated spring provides proper regulating pressure for oversized valve.
• O-ringed end plug positively seals bore to help maintain coast clutch and TCC pressures.