Rear Differential Vent Tube
 

I have an 86 ford bronco with a 9" rear end. Question: What would cause the vent tube to leak gear lube? I just recently replaced the pinion seal hoping for no more leaks...that was 7 days ago. Went in the garage and now it looks like the vent tube was leaking on the floor. Any ideas? Was it pushing out excess fluid? Help!!

Most likely it is overfilled

Sounds like it was overfilled. You should have a hose on the vent tube, if not, it is possible for it to suck water during a heavy rain or big puddle.

The other thing to check is to make sure you do not have a brake line leak since the brake line banjo goes around the vent on some Ford axles (like my 1971 F-100).

Vent Tube
 

Yes the tube is there and clipped in the vertical fashion. I did check it out and the leak is coming from the top of the vent tube and follows the hose down to its lowest point, where as distrubuting the gear lube on the garage floor...I'm thinking at this point it is just overfilled. If anyone thinks otherwise please let me know. Thanks guys! :)

You can also extend it. :)

Vent Tube
 

Excellent idea...do think a garden hose will work....just kidding!!!:)

Overfilling would be my guess too. Either that or driving it on a 45 deg. angle.

If you do any offroading, extending it is a great idea as Mike W suggested. I had mine 38" above the ground and still sucked water into the dif..

Now, all my vent tubes for the axles and t-case are run through the firewall and up under the dash in the cab.

Kevin K.