B1 clutches in listed transmissions are applied in 2^nd and 6^th Gears in conjunction with other clutch packs. As the B1 clutch control valve oscillates and strokes over time, bore deterioration results, which prevents proper hydraulic control of the B1 clutch pack. This can cause flares, harsh shifts, slipping, erratic clutch apply timing, ratio codes and burnt B1 clutches. Reconditioning the bore and installing Sonnax oversized B1 clutch control valve kit 15741-61K restores normal shift operation re-establishing the hydraulic integrity of the B1 circuit.

• Annular groove helps center valve in bore to reduce future side-load wear
• New spring matches OE calibration
• Hardcoat anodized aluminum valve combats premature wear