In GM 4L60-E, 4L65-E abd 4L70-E units, wear at the shift valve spools and bore lands causes loss of critical hydraulic pressure which, depending on the wear location and severity, can result in shift timing/feel complaints, 2nd Gear starts, 3rd clutch failure, 3-4 shift complaints and loss of AFL pressure. Reconditioning the bore and installing Sonnax oversized 3-4 shift valve kit 77754-42K restores hydraulic integrity.

• Hardcoat anodized aluminum valve combats premature wear
• Sonnax spring maintains OE operating pressures and timing