4L80E Manual Valve - Sonnax

Product Description

Sonnax manual valve 34994-16 for GM 4L80-E and 4L85-E transmissions. It replaces the OE manual valve, which tends to bend and wear its bore, and renews manual circuit pressure control.

Specifications

Why it fails

The OE manual valve is long, with relatively narrow spools and minimal valve support. It is prone to bending, and a bent valve causes excess bore wear that lets fluid escape the selected circuits. Symptoms include bent valves, low line rise, delayed engagement and loss of gear.

The Sonnax valve has lengthened spools that ride in the unworn part of the bore for stability and wear prevention, a larger stem diameter than OE, hardcoat anodized aluminum construction to resist wear, and an annular groove on the inboard spool to reduce side-loading.