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Simple Differential Question

Discussion in 'Chevy Trucks' started by clayexi, Jun 16, 2003.

  1. clayexi

    clayexi Junior Member
    Messages: 2

    OK, I've changed my fluid several times over the years, but what is the reason for the rubber hose that is coming off the top of the differential housing? It's plugged and as far as I can see, not needed.

  2. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    It is a vent, and it should not be plugged. It should have a little spring loaded cap on the end, made of plastic. IT might look like a plug, but it is not. If someone before you plugged the hose, you should install a vent cap.

  3. DrMaserati

    DrMaserati Junior Member
    Messages: 11

    To expand on what Chuck said, if you're wondering why it has to be vented, it's to prevent pressure build-up as the unit heats up. Without the vent it will push oil past the seals at the very least. At worst it will blow the seals out.

  4. clayexi

    clayexi Junior Member
    Messages: 2

    Thanks, I'm good-to-go now. That plug was actually a mud clogged vent. I even heard the air escaping when I pulled it off. That positive pressure won't be a problem again.