Something exploded

atalarico

Senior Member
Hey all,

I just noticed a leak under my truck the other day and the very distinct smell of gear oil or something like that. I took a look and saw this carnage...

The first photo (sideways) seems like the source of this leak. This is a hose/tube in my engine bay. I can't tell what this thing is hooked up to, but it kind of looks like it goes down to the power steering rack? What the heck is it supposed to be plugged into in the engine compartment and why does it seem like the little cap that's on the tube isn't actually sealing it.

The second photo shows the drip points. The steering rack boot has been torn for a while, so I knew that.

Third photo is a bit of a zoomed out (sideways for some reason) of the area.

Fourth photo shows a crack that seems to be coming from where my steering wheel connects?

Fifth photo shows a lot of grease getting thrown on to my transmission from my drive shaft. Sixth photo follows that down a bit.

I'm really nervous that this is going to be a bad one. I had initially thought my CV boot tore, and that would have been a much easier fix than whatever the heck is going on here.

I really appreciate the help!
 

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Not so big. Don't sweat it. That hose is the breather for your front diff.

I'm betting you changed front diff fluid at some point and filled it right up to the lip of the fill plug. Then at some point you went for a long drive in 4WD and warmed up the front diff. Then the fluid backs up the breather hose and makes a mess.

Mine did this 2 winters ago after driving for several hours in 4wd at moderate speeds. I believe the service manual says the front diff fluid levels can be a little below the fill plug. It has been covered here before if you search.

I just cleaned mine up and it has never happened since.

Good luck.
 
The first photo is the breather for the front diff. If you drive in 4wd a fair amount, the gear oil heats up, and they can puke out a little gear oil. It wouldn't be a bad idea to check the oil level in the front diff, so it doesn't get too low.

It's hard to say if that's the source of all the oil in your pics, without inspecting it in person.


Edit: As was posted while I was typing.
 
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Not so big. Don't sweat it. That hose is the breather for your front diff.

I'm betting you changed front diff fluid at some point and filled it right up to the lip of the fill plug. Then at some point you went for a long drive in 4WD and warmed up the front diff. Then the fluid backs up the breather hose and makes a mess.

Mine did this 2 winters ago after driving for several hours in 4wd at moderate speeds. I believe the service manual says the front diff fluid levels can be a little below the fill plug. It has been covered here before if you search.

I just cleaned mine up and it has never happened since.

Good luck.

That is exactly what it is! It smelled like gear oil (which is really distinct), but I checked all the places gear oil goes and I didn't see any leaks.

Yes, I topped off the front diff about two weeks ago after forgetting to top it off after a CV axle change back in August. Back then I had put the remnants of a quart I had left over into the diff after the CV axle change, but I forgot to go back and top it off for a while.

I have been driving in 4WD more the past week with the snow we've had in town and the 4 hour round-trips to the ski hills here. In fact, I noticed the very distinct gear oil smell when I stepped out of my truck after arriving at the ski hill last Thursday and I looked under my truck and saw what I thought was my CV boot had torn and sprayed grease everywhere, but it seemed more liquid than moly grease. Yes, there was a good amount of 4WD engaged during that drive.

I guess that's a good feature instead of exploding my diff because it's too full of hot fluid?

I guess I'm going to go to the pressure wash place and spray all of that out at some point. Is there anything special I have to do to close that blow-off valve back up?

Whew...what a relief! Thank you for the reply!
 
The first photo is the breather for the front diff. If you drive in 4wd a fair amount, the gear oil heats up, and they can puke out a little gear oil. It wouldn't be a bad idea to check the oil level in the front diff, so it doesn't get too low.

It's hard to say if that's the source of all the oil in your pics, without inspecting it in person.


Edit: As was posted while I was typing.

Thanks! So, it might be the case that it blew off too much oil and I might need to add some again?
 
Thanks! So, it might be the case that it blew off too much oil and I might need to add some again?

Since you said you topped it off, it was likely just a bit overfilled. Hence the puking out the excess when the oil heated up and expanded from all the 4wd driving. I'd say the level is probably where it needs to be now, but you can check if you're concerned.

As for the breather, there's nothing to fix.

I wouldn't get carried away with a pressure washer though. High pressure from those can force water past oil seals, or into electrical connectors. Both are bad, but the problems they create usually won't show up right away.

If you want I'd probably clean up the gear oil with some brake cleaner on a rag. You don't want to spray brake cleaner at oil seals, either.
 
Since you said you topped it off, it was likely just a bit overfilled. Hence the puking out the excess when the oil heated up and expanded from all the 4wd driving. I'd say the level is probably where it needs to be now, but you can check if you're concerned.

As for the breather, there's nothing to fix.

I wouldn't get carried away with a pressure washer though. High pressure from those can force water past oil seals, or into electrical connectors. Both are bad, but the problems they create usually won't show up right away.

If you want I'd probably clean up the gear oil with some brake cleaner on a rag. You don't want to spray brake cleaner at oil seals, either.

Yeah, good call.

The more I read about this the more I wonder if the breather tube is clogged. This has never happened before, and I think it happened twice during that trip to the mountains last week.

Any tips or tricks to pulling that tube off? Will it leak fluid from the front diff, or only if the front diff is hot and overflowing? I want to try to install a catch can too maybe...(think fuel filter but with the filter removed).
 
I didn't see it mentioned yet, but clean out the breather and tube when you're done. Dirty gear oil in there could clog.
 
Front diff oil. Very normal if you over filled it. I also had the same symptoms after coming home from CO. Once excess oil comes out, you don't have to worry, just drive.
Next time don't fill even a drop above the fill/level plug.
 
Extend the breather tube to the top of the firewall. Then cap with a cheap and clear old style fuel filter. You want the arrow pointed to atmosphere. This allows air to pass through. Prevents contaminated material from falling into the breather tube.

Be sure to check your other breather tubes. If plugged it could start blowing seals.
 
Any tips on how the breather and tube is cleaned?

If excess oil is coming out through the breather (which it is), then it's not clogged.

It wouldn't be a bad idea to pull the breather out of the hose and clean it up with some brake cleaner, let it dry, and then reinstall in the hose. Just so if you were to drive in dusty conditions, the dirt won't stick to the gear oil residue on/in the breather, and then possibly clog it.

An even better idea is to extend the breather up to a higher spot, as was mentioned.

I extended the breather hose higher on my 4Runner, shortly after buying it 18+ years ago.
 
Thanks all! I pulled it off yesterday and it was clear. Cleaned everything up and pulled the cap off of the breather too to clean out the dirt that accumulated. I'm still a bit concerned about that crack on that part of my steering shaft, but I think I've seen that before years ago and it hasn't gotten any worse.

I also taped up the steering rack boot that was torn. Hopefully that holds for a while longer until I can get a new/used daily driver and venture into replacing that rack myself in the next year. I got it replaced as soon as I got the truck but it wasn't a great shop and I'm sure they just used a reman'd one or something.

Anyway, just happy that this wasn't the CV axle I just replaced with the nice CVJ silicone booted reman or anything.

Cheers!
 
This is off topic op, but what exactly are you doing with that red wings jersey in your profile picture?? Are you an Av's fan? If so we may have to drop the gloves
 
This is off topic op, but what exactly are you doing with that red wings jersey in your profile picture?? Are you an Av's fan? If so we may have to drop the gloves

Good eye! I'm a born and bred Detroit kid that moved to Denver in 2009. I was raised on Red Wings hockey (but also just good hockey in general). While the Avs/Wings rivalry is all but dead these days (no more players that were even around then really, and different conferences now), but going to the games or wearing a Wings jersey in Denver is still a hoot.

I'm also an avid mountaineer, so I tend to bring the jersey with me when I am summiting something. This was on the summit of a 13'er in the winter. So, let's drop the gloves, but to raise some pints of beer instead!
 
Good eye! I'm a born and bred Detroit kid that moved to Denver in 2009. I was raised on Red Wings hockey (but also just good hockey in general). While the Avs/Wings rivalry is all but dead these days (no more players that were even around then really, and different conferences now), but going to the games or wearing a Wings jersey in Denver is still a hoot.

I'm also an avid mountaineer, so I tend to bring the jersey with me when I am summiting something. This was on the summit of a 13'er in the winter. So, let's drop the gloves, but to raise some pints of beer instead!

Well in that case, we should be best friends.

That was the best rivalry in sports history, in my opinion. I was born near oscoda mi, before my dad got orders to Japan and we moved. But he grew up in Michigan, and I inherited my Michigan fanship from dad. I played ice hockey (still play) growing up and became an avid red wings fan at about 12. I was a teenager playing high school hockey when the rivalry was going on, and we lived in Cheyenne, which is a little over an hour from you. And most of my friends were Av's fans, so I got big into the rivalry. Watching those playoff series are literally some of my best memories ever. Our house was nuts those days. Yelling, throwing stuff, jumping around the room, decked out in red wings apparel. Man that was an exciting rivalry! I'll never forget when McCarty destroyed Claude Lemieux in retaliation for the cowardly hit on Draper. I still wear McCarty's jersey when I play drop in hockey on Friday nights.
 

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