The B1 band in Aisin AW TF-80SC and TF-81SC transmissions is applied in 2nd and 6th Gears in conjunction with other clutch packs. As the B1 band control valve oscillates and strokes over time, bore deterioration results which prevents proper hydraulic control of the B1 band. This can cause flares, harsh shifts, slipping, erratic clutch apply timing, ratio codes and a burnt B1 band. Reconditioning the bore and installing Sonnax B1 band control valve kit 39741-22K restores normal shift operation and feel by re-establishing the hydraulic integrity of the B1 circuit.

• Sonnax valve is hardcoat anodized aluminum to provide wear resistance
• Annular grooves have been added to the valve for better centering in the bore
• The highly wear-resistant Sonnax sleeve provides over 80% more support than the OE casting
• A new spring is included to allow proper calibration