In GM 5L40-E and 5L50-E transmissions, the low pressure control valve applies in 1st, 2nd or 3rd Gear coast conditions, when engine braking is needed. Depending on the gear and solenoid states, 1-2-3 regulated fluid pressure is routed through this valve to provide engine braking through a controlled apply of the low/reverse clutch, 2nd coast clutch or OD clutch. If the bore has excessive wear, this regulated oil pressure is open to exhaust, resulting in 3-2-1 bumps on coast downshifts, no engine braking, and/or clutch failure.

Sonnax oversized low pressure control valve kit 55211-17K is easily installed into a refurbished bore and incorporates design upgrades to prevent future wear concerns.

• Hardcoat anodized aluminum valve combats premature wear
• Outboard spool is 74% longer than the OE design, adding stability and critical hydraulic sealing for the 1-2-3 regulated oil pressure
• An annular groove has been added to the outboard spool to hydraulically center the valve in the bore and prevent wear
• Includes oversized end plug