Front diff breather puked

Hey guys, I rarely post new threads, but this has got me stumped.

Today I drove my truck to work (~51 miles of interstate) and when I got there I noticed oil all over the underside of the driver side front fender well. Investigated further and saw that the oil was all over the UCA, drivers side frame, driveline, gas tank skid, rear axle, yaddi yaddi yadda. Popped the hood and saw the cause to be from the breather tube from the front diff (which made sense since the oil smelled like diff fluid).

The thing that has me confused is that I changed the front diff fluid approx 8,000 miles ago and know for SURE that I did not overfill, as I checked it for the next two weeks after I changed it. Since I've changed it, I've made multiple long, highway drives and also plenty of 4x4 trips. So why the big release?

Once I got home I took out the fill plug to see where the level was and just a little dripped out, which has me perplexed since so much vomited out the tube. I then checked the breather end and it seems functional, as once it was clean I was able to push air through it with my mouth.

The only thing I can think of is maybe before the explosion the breather end was plugged, and now its not?

Thoughts?

 

I'm not sure myself. I had something similar happend to me here in Fairbanks a couple of weeks ago, but I ascribed it to rather chilly temperatures in January. (-26º below average for the entire month. Lowest was -51ºF and better than a week at -40F). I noticed my front differential breather also puked a bit of

$30 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 synthetic, but not nearly as much as you. I have to say that I often will use my 4x4 several times in my trip in and out of town. perhaps it had something to do with differential temperatures as I'm sure the oil is heating at different rates throughout the differential. I don't know otherwise what would cause it. Sorry for not knowing. I'm just thinking as I type.

 

I had the same thing happen in my 02 right before I traded it. It wasn't an all the time thing, and wan't ever a lot...but it would purge itself. I tracked it down to the front diff, and it didn't matter if I was in 4wd or 2wd when it would leak. I checked the fluid and it was at the proper level (Redline BTW). Never could figure it out, and ended up trading the truck. It really was a mystery, and I'd be interested to see if there was a simple solution to it.

 

Thanks for the replies, not cold at all here in NM so that cant be it. For now I'll just keep an eye on it, if it does it again I will just go buy a new valve. Will keep everyone posted.

 

Mine has done this twice. Just check the oil level and move along. Oil gets in the hose somehow and out it comes with the temperature/pressure change. Worse things could be happening, this is not one of those things.

 

The breather on the front differential isn't a one-way valve. It is just a open fitting with a breather cap that freely allows air in and out. If you read any of the threads on the rear differential breather mod, most replace the one-way valve on the rear with a two-way breather like the front. My guess is you got gear lube in the breather hose with an air bubble behind it that wouldn't let the lube drain back down. As the temp in your diff went up, it pushed the bubble with the lube above it out the breather.

It isn't anything to worry about. My taco does this often in the wintertime. It is nothing more than enough lube to cause 1 drop on the ground. I have checked my lube level, and it is always spot on. I have also seen the rear diff on my motorcycle do this when it is cooler out.

 

Mine did this recently, but I also have a small leak at the rear oil seal on the front diff. Not sure if one had something to do with the other or not. I hope to change the oil seal this weekend and hopefully it will not happen again.