This transmission gasket seals the joint between the gearbox housing and its cover, preventing oil leakage and maintaining internal pressure. It sits at the mating face of the transmission case, where it contains the lubricating oil that cools and protects the gear train and bearings. A degraded gasket allows oil to weep externally, which can lead to low fluid level and eventual gear or bearing damage. The gasket is cut to match the original housing profile, ensuring correct compression across the entire sealing surface. On reinstallation, clean both mating faces thoroughly and apply the manufacturer's specified sealant pattern before torquing the cover bolts to spec.