Front Gear Oil Leak

[biswrest]

I am looking for a little help, I have a 2003 AWD Mountianeer. There is a dead end tube up by the front drivers side door that has blew gear oil out twice now. I also have a front end hum noise. A little background, I recently blew a tire out away from home, so I put two pretty new Continentals on the front. I drove it home about (1,000 miles) with the two Continentals on the front and nearly bald Goodyears on the back on Sunday. About sixty miles from home I notice I had some leaking gear oil. I got it home and put about 1/2 quart in the front differential. I then matched up and got two new continentals on yesterday. It blew more gear oil out this morning, and it does seem like there is a hum coming from the front.
Any thoughts would be most welcome
Biswrest

 

[Dave8338]

The hum could be front wheel bearings OR inner axle bearings. On the AWD Mercs and Lincolns, as you know, need tires replaced as an entire set. You likely didn't hurt anything but the front diff could have gotten hot as a result of the mismatched tires. Also, I would rotate the used front tires to the rear and see if the noise follows the rotate OR if the hum is still present. Let us know what you find...

 

[biswrest]

Dave,
So you think that when the differential gets hot, it blows it out that relief valve? I can rotate the tires tonight to see what happens. I have replaced both front wheel bearings and hubs already and that was definitely making a different noise.

 

[Dave8338]

Yes... there is a vent tube that when things get hot, allows for fluid vapor to be vented off. If the diff is over filled, it can and will drain the fluid out the vent tube.

 

[biswrest]

I changed all the fluid, rear and front differential and the transfer case. It still made the hum. I then rotated the tires, like you said and I drove it for ten minutes and everything sounded normal. It will get driven more tomorrow, so i will see if that worked. Thanks Dave

 

[biswrest]

Dave,
What do you think?, the used tires I bought have 9/32" of tread and the new ones that have the same brand Continental Contitrac TR have 11/32" of tread, should I replace the used ones as well?
Biswrest