GM 4L60-E, 4L65-E and 4L70-E transmissions often have trouble shifting into or holding 4th Gear due to excess wear in the sequence valve bore. This wear allows vital 4th Gear accumulator oil to exhaust, resulting in deficient servo apply pressure. Consequences are slipping or no 4th Gear operation followed closely by a burnt band. Leaking at the OE end plug also allows oil loss that can leave 4th Gear inoperable. Re-establish hydraulic control and restore normal operation by reconditioning the bore and installing Sonnax oversized 4-3 sequence valve kit 77964-04K.

• O-Ringed end plug helps prevent 4th Gear oil loss
• Hardcoat anodized aluminum valves combat premature wear