Features and Benefits:Press fit rear seal to engine block & crankshaft for proper fitment of inner & outer seal body;Services GM/ISUZU 6.6L Duramax 2001+ GMT800, 2500HD & 3500. Installation instructions: Set new seal on inner body of tool;Attach outside ring of tool to the end of the crankshaft assembly, turn forcing screw to press in new seal;Compare to GM Factory tool J-44642;Press fit rear seal to engine block & crankshaft for proper fitment of inner & outer seal body. Services GM/ISUZU 6.6L Duramax 2001+ GMT800, 2500HD & 3500. Installation instructions: Set new seal on inner body of tool. Attach outside ring of tool to the end of the crankshaft assembly, turn forcing screw to press in new seal. Compare to GM Factory tool J-44642.