Rear axle vent puked some fluid

[dan50]

Took the Bronco out for a spin tonight to go run some errands. Get out of the store, walk towards the Bronco, and see a puddle under the driver rear section of the Bronco. Get up underneath and I see tons of spray of red fluid - like ATF Type F or Mercon - and it's coming from where the vent tube on the axle is. I have a hose attached on it, and the hose runs about 6" upwards. The brake line that is supposed to slip OVER the vent tube is zip tied to the side of it because the vent tube was too short to slip all the way through the brake line hole (if you've done the rear brake hose that should make sense).

1) What is the vent needed for? I drove for a year with a bolt in there holding the brake hose in place and it seemed to work fine, but I put the tube and hose back after I was told it was necessary.

2) Why the hell is the rear axle puking??? Last month I drove 400 miles without any issues, tonight I drive 15 miles and it pukes 1/4 to 1/2 a cup.

Thanks...
Dan

[blazinchuck]

The axle needs to breath. If it doesn't have a vent it will blow the seals. If the seals blow and you go through water then water will get in. If water gets in the oil will foam up and puke out the vent tube.

2X been there

[bucketobolts]

Is it over filled? There should only be enough oil in the axle tube to keep the wheel bearings lubed. Maybe 1/4" or less.

If there is too much it could be slinging off of the axle itself and venting.

Another thought is maybe a diff bearing going or too much preload on the pinion? Causing excessive heat making the oil boil?

[broncomatt]

try pulling the fill plug and checking the fluid level, and the quality of the fluid.It should be light brown and clear. If it is milky than water has gotten in it.
The ring and pinion build heat, the changing of the temp causes the fluid to expands some. That is one of the big reasons you need a vent.
The fluid should not be red, that sounds like atf, not good for bearings or ring and pinion.
broncomatt

[dan50]

I've put maybe 6000 miles on this thing since I bought it several years ago, and to be honest I have no idea what the fluid level is in the carrier, nor do I know what fluid is in there. But in all those miles, I've never had an overflow issue from the axle. Here are some pictures. The axle is soaked right where the vent screws in, and the exhaust, frame rail, and undercarriage is soaked in two locations - 1) where the vent hose ends, and 2) where the vent itself would shoot out if the rubber hose was loose... which it was since the zip tie I had on there came off.

I wiped it down, used a clamp on the hose that's on the axle vent, and took the back roads home. No new fluid leakage detected yet...