26-88397A1 Driveshaft Housing Upper Unit Seal Kit 88397A1 For Mercruiser Stern Drive Alpha One Gen II 26-88397A1 Sierra 18-2644 The 26-88397A1 Driveshaft Housing Upper Unit Seal Kit is designed for use with the upper unit of Mercruiser Stern Drive systems.This seal kit replaces worn factory seals that can degrade due to exposure to water, salt, and mechanical stress.It includes all necessary components for a complete replacement such as the main seal, O-rings, and related parts that work together to maintain a watertight and oil-tight seal.This kit is compatible with Mercruiser Alpha One Gen II and Sierra 18-2644 models, providing a direct fit for these applications.The 88397A1 is equivalent to 26-88397A1 and refers to the same seal assembly.The upper unit in a stern drive system transfers power from the engine to the propeller and contains the driveshaft.Over time, seals in this area may wear, allowing water to enter and potentially cause corrosion, bearing damage, or internal engine issues.Replacing the seals helps protect internal components, retain lubrication, and support consistent.Constructed from marine-grade materials, the kit resists corrosion and performs reliably under varying temperature and environmental conditions.It includes all required seals and O-rings, allowing for a full service without sourcing individual components.The design supports straightforward installation on specified models, proper alignment and sealing function.Regular maintenance using this seal kit can help prevent more extensive repairs by addressing seal wear before it leads to larger mechanical problems.It serves as a practical solution for preserving the integrity and function of the driveshaft housing in compatible stern drive units.