*** BEFORE ORDERING, PLEASE VERIFY REPLACEMENT SEAL PART NUMBER… For engines built with seals p/n: 1817867C93, 1817767C1 and/or 1817865C1, use tool ZTSE4749 (Seal Outside Dia. 166mm). For Engines built with seal 1809964C92, use Tool ZTSE2535C (Seal Outside Dia. 156mm). *** This tool is designed to install and correctly position both crankshaft rear oil seal and wear sleeve. This tool replaces ZTSE4374B.