Hotrod57; I have the 9" 31 spline .I have a O ring seal on the bearings.I talked to the mfgr. the possibilities of it leaking with just the O ring and he said he had no failures reported.He said if I was not comfortable with it to go and pick up the bearing seals(77 Torino) at Car Quest Pt# 473228 .I did feel uncomfortable with just the O ring and I put in the Seals he recommended.So far no problems.