rear axle vent leaks-please help.

[jkcamro67]

I have a 1967 camaro with a 9" rear end. I run Red Line gear oil. I noticed that the axle housing vent was leaking. I added about 16" of hose upward and put the vent at the end of the hose. I noticed that the vent still leaks. I dont know what would cause it or how to fix it. I filled the rear end to the bottom of the fill plug so I dont think it could be overfilled. I dont know what would cause it to fill up the vent line and leak out. Any help would be great. Thanks.