A couple weeks ago we took the Runner to Durango on a ski trip. When we got to the mountain, I put it in 4WD to get through the snowy/icy parking lot. When I pulled up to one of the front spots, I did a little poser-park job on the snow embankment. When I got out, I smelled gear oil. Upon further investigation, I found that oil had "exploded" out of my front diff's extended breather hose (in the engine bay). I checked the breather cap, and it moved fine, with no mud or anything caked on to it.

Any ideas as to why my front diff breather barfed oil? It was cold, like 12 degrees. Could ice have formed in the tube and the pressure blasted it out?

 

Altitude?

 

Its probably because it has never been in the snow before!

 

Yeah, my rig was so excited she puked!

 

Hope it's fine Christian?

 

Definately check the level to make sure you aren't low.
Must have been some sort of blockage that let go violently.
You have a check valve on the end of the breather tube?

 

Bamachem's did the same thing last week in a similar situation-very cold, shifted into 4wd, steep incline. This is what he deduced...or something like this...

A combination of the temperature and the incline caused some air that is in the diff, cause it ain't full of fluid as you know, to be pushed up to the breather when you inclined the front end in 4wd and thus it got pooted out w/ some fluid.

His seems fine now. You might PM for some more details.

 

Thanks, I will direct him to this thread. Maybe he can add some input.

Thanks guys.

Jamie-

Yes, all I did was rip the "head" off the stock breather tube, add some yellow line, and place the head back on the end of the yellow line. I almost wonder if somewhere in that extension I created a problem. I have had this "mod" for a 6 months with no problems. So I am beginning to wonder if temperature and altitude played a role. Nothing wrong with checking the fluid. After all, this is the donor rigs' 4.30 diff. But, the guy had an impeccable service history from the dealer, including diff fluid changes.

I guess it was better that it exploded out of the breather than the output seal.

 

Definately.....you don't want any pressure building in there and maybe blowing a seal (most axle leaks are from exactly this).
Altitude, temp and inclination certainly can all play a role in what you described.

 

did you have it filled up before you went?mine slung oil all the way up the mountains but on the way down it didn't.Yes it was full.

 

No, I didn't fill it up recently.

The next time I put it in 4WD, which will most likely be local, I will see what happens. If it doesn't puke, I guess I will write it off to the elevation and temperature.

 

Mine did it going to the top of a mountain when it was about 20* outside. I put it in 4wd and went up the steep trail for over a mile. At the top, I got out and my front diff had puked. I figured out that when on an incline, the air bubble you have in your diff shifts to the front, leaving the diff breather tube submerged. Then using 4WD in cold weather for an extended amount heated the fluid and air in the diff. Thermal expansion kicked in, and the only place anything could expand to releive any pressure was to force gear lube out the breather. I powerwashed it off and have checked it several times and have driven about 600 miles since then and all is fine.

 

Wow, I never thought of a bubble and thermo-expansion. Cool stuff. I am gonna write this one off I think. Maybe I give the fluid a check, but other than that sounds like I am good to go.

Thanks for responding.

 

I have smelled gear oil from the front breather when I get crazy on snow runs, but I've never seen it come out the top. It is almost impossible to get the breather to go uphill the entire way, I have a P trap in mine. get a little splashed up in there, build pressure in the front diff. by workin' it and then it all pukes out the top. SAS is going to fix that.

I have a fuel filter on the top of my breathers. Might be how the smelly air can get out, but the slower oil collects in the filter matrix and then drips back down the tube later.

 

You want gear oil? Check the back of my rig

Shes going in tomorrow to the stealership for a $700 rear axel seals and drums... shoot me now

 

Ouch, I guess it could be worse.

 

Um, for what it's worth...

I live in the northeast, and the weather has been particularly bad the last month or so. I climb an 18% grade for about 2miles up to my house. When the roads are bad, I use 4hi - never had any problems with the front diff, so I'd question temp as the culprit.

 

I was only using temp as a reference because in my case, the front diff went from "cold" to "operating temp" while on an incline the whole time. Who knows if that's really what happened, but that's about all I can come up w/ to explain it.

 

I've had it happen to me when in 4WD. I don't remember the camber situation, but it hasn't happened since.

 

Pukes out of my ARB compressor in cold weather, front and rear if it's really cold. Ran up to Crown King yesterday, cleaned gear oil mist from under the hood. Over the years I've found the Toy diffs to be really tight and spit up lube once and a while. Better than being clogged...

Mike