Tool, Reamer For 77964-04K, 4L60-E, 4L65-E, 4L70-E, GM

A worn 3-4 relay/4-3 sequence valve body bore can cause a no 4th gear situation in a 4L60 or 4L60-E. Due to the constant valve oscillation, wear occurs at the 4th accumulator circuit. This can lower 4th gear pressure by as much as 20-25 psi, resulting in lower servo apply pressure or no 4th gear. Leakage also occurs at the end plug, due to valve hammering. This allows 4th signal oil loss which can result in a no 4th gear situation. Sonnax now offers two oversized 3-4 relay and 4-3 sequence valve kits, 77964-01K for the 4L60 and 77964-04K for the 4L60-E.

Features & Benefits

Critical valve spools have been made larger to restore hydraulic integrity to the valve bore.
Each kit includes an o-ringed end plug to prevent 4th gear oil loss.
Valves for the 4L60 are made from hardened steel to duplicate the OEM material for use in the cast-iron valve body.
Valves for the 4L60-E are made from hard-coat anodized aluminum to provide longer life, resist wear and maintain critical clearances in the aluminum valve body.
Sonnax reamer 77964-RM for the 4L60 and 77964-RM2 for the 4L60-E allows you to re-establish the bore size for the oversized valve kits.