Wear in the main pressure regulator bore and on the outboard spool area of the valve is common in GM 10L60/80/90 (Gen. 2) 10-speed RWD transmissions. This wear minimizes line pressure control resulting in delayed shift engagement, poor shift quality and burnt clutches.

Reconditioning the bore and installing Sonnax oversized main pressure regulator valve kit 105740-21K eliminates the leakage of line pressure signal oil to exhaust with the incorporation of annular grooves on the outboard and inboard spools of the valve. The O-ringed end plug provides a positive seal and prevents critical signal fluid from leaking to exhaust. Both of these Sonnax features ensure your units will have proper line pressure control through all drive ranges.

• O-Ringed end plug provides positive seal to prevent critical signal fluid from leaking to exhaust
• Hardcoat anodized aluminum valve combats premature wear
• Annular grooves help center the valve in the bore to reduce future side-load wear
• Included are two new springs that restore OE pressure specifications