Im at a loss here... My 98 mountaineer keeps throwing rear end oil out the vent tube.. Why does it keep doing this?? its been doing this for a while and had to change an axle seal, I think because of this. It stopped doing this for a little while after I changed the seals and put in new oil.. Its not over full.. When it stopped I figured it was because the oil was old and was foaming or something.. But now its back to doing it again... The tube is not plugged.. Why does it keep doing this???

 

Does the rear end seem hot when this is happening? It seems like the oil is either overfilled or getting hot if it's coming out the vent tube. What type and weight oil did you fill it with after you changed the seal? Are both rear tires the same type, size, with the same mileage, and properly inflated? Does your Mountaineer have the LSD or an open differential?

I had a plugged vent on my 2000 Mountaineer which I suspect is the reason I was getting oil leaking past the axle seals, but I had not experienced oil coming out the vent tube once I refilled after replacing the bearings, seals, and cleaning out the nipple and vent tube.

-Rod

 

make sure the oil is the correct type and weight for the application.
Take special note of whether or not hypoid oil is used.

Maybe there's water in there causing an overfill condition?

 

I know its not over full. I checked it yesterday to make sure. It was throwing oil out the tube before I changed the axle seals. I filled it with 75w140 full synthetic for limited slip, thats what it calls for. It is a limited slip rear end. Tires are all the same size.. These tires have been on it for a couple years.. I just don't understand why it would, or could throw oil out that tube, its not like the tube is where most of the oil even is, its in the axle tube, and it has to go up the tube which is about 10 inches long. I have not checked to see how hot the rear end is after driving it.