Sometimes The slip joke leaks out of the vent hole, Other times it leaks around the cap. Some say REPALCING the slip yoke fixes it but some are not cheap or are of UNOBTAINIUM!
Not at all how a how to video so no one comment “YOU DID NOT SHOW ANYTHING” I don’t care. If you cannot figure out how to clean a surface and apply some RTV with a screw driver, Don’t try to comment.
These Chevy or GMC trucks seem to do this alot. But It seems any Spicer or AAM Drive shaft assembly with a slip yoke from any make and model can have this issue.