Clogged Front Diff Breather

Agreed man. Hopefully the video above for replacements helps people avoid a destroyed rear diff. What I don't understand is how mine has probably been clogged for years and I've never seen it leak that's what I can't figure out. Maybe I just got lucky

 

Update the hose/breather combo (the smaller diameter breather) has actually been discontinued. You can't buy them from the parts shop at the dealer. If anyone knows where to get the smaller diameter breather or a replacement for it that would be much appreciated.

 

It's just a breather- if a part works for the 2nd gen, just adapt it and make it work for the 1st gen. Or just two of the ones you can get for the 1st gen and adapt it...

 

Normally, the heat increases slowly, so is the related pressure, and it has time to gradually escape without causing leaks. But when you submerge a warm axle in cold water, sudden drop in pressure sucks that water thru the axle seals.

 

That's the most common explanation I've seen also, and I can see how that happens in those circumstances. Thing is, those circumstances don't really apply to me. I'm at 79 feet elevation, and the daily low temps here have been lower 30's...at the lowest.

Maybe in my case it's some combination of cooler temperatures and the breather plugs acting up.

 

No real confirmation. Just the websites stating those parts aren't compatible with my year. If I was a betting man, I'd say they are, but no way to tell for sure.

I'm not even 100% sure on how these plugs are supposed to work. I've seen them referred to as "one-way" and "two-way" valves. If they are supposed to be one-way, and let fluid/air out of the hose, but not let anything in the hose, then my smaller diameter one is currently working correctly, and the larger one is allowing two-way traffic.

 

I’m no expert but I have to imagine they’re meant to be 2-way in order to always equalize the pressure. Otherwise a vacuum could form in the housing in response to temperature or elevation changes, which could be equally problematic to sealing.

I have a brand new spare in the garage, bought for a rear diff. I can go breathe through it later if you want

 

Discontinued?? Now we really need to find out if those parts for the 2Gen will work on ours.

 

All joking aside, we need you to go blow and suck on that thing and let us know what happens!

 

Update from the parts department where I live. The aforementioned breather plug on Amazon is indeed the correct part for the larger diameter hose (part number 90930-03136):

$7 Toyota Breather Plug - 90930-03136

https://www.amazon.com/TOYOTA-90930-03136-Toyoya-PLUG-BREATHER/dp/B01FSZ9YY4

Part 90930-A3001 is the breather for the rear diff.

 

I'm probably going to throw the other smaller diameter breather on mine from this image. The larger diameter breather matches what my part store gave me I bet it's the correct part. Looks identical too.

Where did you buy those parts from?

 

So I cleaned up the affected area really well (around the front diff breather/ADD valves and down around the skid plate where I assumed the burped diff fluid drained to. Looks like the front pinion seal is leaking (found new diff fluid on the skid plate and around pinion seal after it was cleaned and after I freed up the breathers. No fluid looks like it came out of the breathers this time.) - probably due to pressure/temp build ups in the diff due to the clogged breather like we were talking about previously in this thread. For anyone who sees this it may be wise to check these breathers at some cadence to ensure they aren't clogged so your diff doesn't wind up leaking.

 

I'm sure it's my own ignorance on the topic, but I didn't understand how we can have a burping/leaking breather at the same time that we are having a clogged breather that is causing leaks to spring elsewhere. If the breather is leaking or burping, didn't that mean it is not clogged?

I am suspicious of the amount of gear oil that I see on basically everything between the skid plate and the breather plugs. I've been hoping that all of it has come through the breathers, but I'm worried there is also a leak somewhere else. Impossible to tell until I can get it all cleaned up. And I've been wondering how and where I'm going to even be able to do that part.

 

I think when the breather burped the gear oil dried up/gunked up the breather. That's what it looked like happened to mine. The gunking didn't let the diff breathe so the relieve the pressure the pinion seal (e.g. the seal between the front diff and front driveshaft) blew to let the the hot pressurized air escape. Now even though the breather's are free there is still a blown pinion seal which is allowing gear oil to leak.

For the larger diameter breather - part 90930-3136 (I was able to buy this at my local dealer) -

$7 Toyota Breather Plug - 90930-03136

Toyota Breather Plug - 90930-03136
For the smaller diameter breather I searched the part number posted by someone else earlier in this chat and found this guy - https://www.toyotapartsdeal.com/oem/toyota~filter~assy~air~17810-51010.html

I did purchase the larger diameter breather from autozone but it appears to only let air in and not out. I decided to also check the one I get from the dealer to make sure they match before I throw one on there

 

Re: "dried up/gunked look"... with diff fluids, it's not going to take very long to look that way, and actually look a lot worse than it probably is. It's thick/viscous stuff that attracts and catches everything: dust, grit, salt: name it. It makes a complete mess and it doesn't evaporate or wash off in the rain: it slowly migrates from the source. I have had diff covers with slow leaks and they were a mess in no time even with a small and slow leak. (it's a great rust preventative though

 

Yeah man once I cleaned it up it actually looked pretty nice. It's too late for me though I have a leak. Honestly I would've found this earlier had I taken the skid plate off. The skid plate caught all of it and I didn't see the leak.

 

What sort of job is it going to be to fix that leak between the diff and the driveshaft?

Also, since you've obtained a new one of the larger diameter breather plugs from the dealer, can you confirm if it acts as a one-way or two-way valve? I think it's weird that your AutoZone part acted as a one-way, BUT only in the direction of letting air into the hose. I thought these are meant to be one-way relief valves, meaning they should only let air or fluid out of the breather hose, and should passively close to prevent anything from entering.

 

Not sure haven't spent much time looking into it - will check back in when I find out. I know we will at least have to disconnect the front driveshaft and drain the front diff fluid and refill or replace it.

Still waiting on the dealer should have the part tomorrow or Wednesday will check the directionality when I get the part.

 

Getting back here. Autzone plug and dealer plug appear to both works as replacements. Autozone actually was not one way I just thought the air coming out of the valve was coming out of my mouth it wasn't. I confirmed by blowing air through the valves and shutting them and the airflow stopped coming out of the valves. I also blew through the clogged valve that I freed - behaves the exact same way as the two new ones. I threw the OEM part (part 90930-3136) on just in case seems to work just fine.

 

Update https://www.toyotapartsdeal.com/oem/toyota~filter~assy~air~17810-51010.html is the wrong part