Pressure in differential

[1948 santa]

Anyone know what the PSI specks would be on a differential vent valve for my 69 Roadrunner? When I remove the fill plug to check differential oil level, pressure escapes. I cleaned the valve and now tests at 2.5 PSI.

 

[Mogre]

I believe it is strictly a vent and it should not hold any pressure.

 

[PUNKN8R]

I do agree if your differential built up pressure I believe it would have a tendency to blow axle seals regardless what pressure, I think a vent should be open to air. Take for instance the vent on your fuel tank, or a vent on a hydraulic tank. Correct me if I am wrong enquiring minds want to know ??

 

[zyzzyx]

You are correct! The vent is supposed to "vent" any pressure that builds up due to the heating and expansion of the fluid. If the housing develops ANY pressure, it will end up in places that you don't want fluid!

Your vent is not working, and you need to fix it fast! Pull your drums and check for wetness near your brake shoes. Good luck!

 

[Hemi Rebel]

Yeah, it only takes 2 psi to cause a leaky seal

 

[Kern Dog]

This one tripped me out. I have never heard of an axle doing this. I have had gear oil weep from the vent before though.