diff vent
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,618
Likes: 241
From: Russell Ontario
St. Jude Donor '09
diff vent
Just wondering I'm always tinkering and was under the car and decided to check the diff oil level , car was not driven in a few days , when I took the bolt out I had a little air pressure "puff" out the diff, so I thought the vent is plugged , but it was not . Weird not worried just curious, Ron 
Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
It is normal for the diff to be under vacuum after it has cooled after a drive. This is an indication that your vent is working properly. So, when you open your fill plug, you should here a rush of air entering the diff. Now, you say that you felt a puff of air coming out of the diff indicating that there was a build up of positive pressure. This would indicate a defective vent.
What you now need to do is be sure about what you felt. Was it a woosh of air entering the fill hole or was it a woosh of air exiting?
What you now need to do is be sure about what you felt. Was it a woosh of air entering the fill hole or was it a woosh of air exiting?
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,618
Likes: 241
From: Russell Ontario
St. Jude Donor '09
I'm sure it was a "whoosh" of air coming out like a puff, not extreme but enough to know the vent must be plugged , but it moves nice and free , no leaks anywhere, and the level was bang on. Now you say vacuum , is the vent a one way vent . Ron
Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
Yes it is a one way vent. It will allow release of pressure (and sometimes fluid) but will seal and not allow anything in thus, the vacuum buildup after cooldown. This helps with keeping the seals from leaking. Now, if you say you had positive pressure when you opened your vent plug, then that is not good. It will eventually cause leaks and also indicates a stuck or malfunctioning vent.
Drifting
Joined: Mar 2008
Posts: 1,900
Likes: 2
From: Nixa Missouri
Not trying to steal the thread, but to replace the vent, is it a press in cap style vent? I looked a my manual and didnt see any info on how to remove the vent, but it looks like its a pull out and press in the new cap type, if I'm making any since?
Thanks
Thanks
Thread Starter
Melting Slicks
Joined: Apr 2008
Posts: 2,618
Likes: 241
From: Russell Ontario
St. Jude Donor '09
Well all good points but I'll have to look again and see if it's a outburst or inburst, then I'll know for sure . I'm used to the air pressure inside cause the vents are plugged . I'll get back to this has I'm curious now.Ron
