The rubber seals between the center support in the case and the machined surface of the valve body are prone to leakage over time. In GM 6L45, 6L50, 6L80, 6L90 units, this can result in continuous line pressure and lube flow loss, as well as clutch apply leakage in Reverse, 2nd and 6th. Installation of the Sonnax center support seal kit 104740-14K will prevent any leakage that occurs due to a gap between the rubber OE seals and the valve body or center support.