Differential Breather Mod for Dummies (Pics)

Finally got a new shipment of round tuits and did this mod today. Stupidly simple with these excellent directions by Neubs.

Hardest part was getting the side panel out. Broke one of the 4 tabs that hold it in. No biggie to me though. Maybe best not done when its 20 degrees out.

Did not run the hose to through the gas fill but left it free way up inside the bed side near the top rail. I'll decide if I want to permanently affix the new breather to the gas filler area or the cubby or the bed side later when it's warmer.

 

So if I understand this correctly, It's not only about changing the location of the breather, but also about changing out the one-way breather to the two-way breather? IF you were to change the location of the breather but use the OEM one-way breather you are essentially not fixing the problem???

wouldn't it be better to just re-use the one-way breather so that if you do go through some really high water the, the breather closes and doesn't draw water straight in....???

 

The one way breather still allows pressure to build up for axle seals to handle no matter where you put it. The oem one way is also threaded and short threads, not sure how good hose would work trying to clamp it on. With the 2 way breather relocated up high there is way less chance of water getting in up there and it won't build up pressure for the axle seals to have to manage.

 

its actually not about your diff building up pressure, it's more about you diff having a lower pressure then it's surroundings. I found a vid on here that explains it pretty well.

your diff is always pretty warm and most of the time outgasing through your breather, but when you go into water it rapidly cools it which creates neg pressure is your diff and closes the breather which then causes water to be pulled in through your seals. SO, to counter this you need to 2 way breather to make sure the pressure in your diff stays constant.

I think I answered my own question now, thanks a lot!!

I was just thinking that with the 2 way breather it would be easier to get water in through the breather if you were in really high water since there would be nothing stopping it. I guess the only solution would be to have the breather as HIGH as possible!!

 

All correct (not about pressure building - but the temp differential). The hot and quickly cooled differential creates a vacuum in the differential due to the air inside condensing with the now cold differential. This draws air in. If you have a one way breather, it will draw water in through the seals of the differential. Rather with a 2 way breather, it will draw air in through it instead (or water if you located it very low).

 

So I guess the fluid and air inside the housing getting hot doesn't expand any right? Wrong. It's both. The fluid expands as it warms and the one way breather holds pressure in to a certain point making the seals do more work & the cold water dunking thing. I fully understand the dynamics of throwin hot axle in cold water but thanks for the reminder. Can you explain why, (with no water or temp inversion involved), there is a pressure release when removing the oem breather after the thing has sat overnight and everything has cooled? I want my axle seals to hold fluid, not pressure in either direction.

 

Yeah, that's exactly what I had already said. I wasn't trying to explain anything to you buddy, I was simply answering my own question so that members knew they didn't have to spend time (like you) responding to me!

Are you sure when you removed the OEM breather that it was RELEASING pressure? Cause (also what I had previously said) if it was a one-way breather it could have been PULLING air in from the overnight cooling of the air and fluid creating a vacuum. both would have made a hissing noise?

 

So easy I can't believe I hadn't done it years ago. I wanted to clear some space off on my work bench and the parts for this mod were taking up space....They aren't any more.

Guess it might be time to swap diff fluid to clean whatever crap out might be in there.

 

Sorry, didn't get that based off the "diff not actually building pressure" statement.

Either way, all scientific whatever anyone wants to analyze or how they wanna phrase it, the axle seals are uneccessarily dealing with pressure they don't need to be from a one way breather and by doing this mod they won't have to and water won't enter unless submersing the whole truck to past whatever height you place the 2 way.

 

I completed the breather mod this past Saturday but I routed the new location to the covered storage compartment in the bed wall instead of the location shown in the pics. I was afraid that the double sticky tape that holds the little "pop-out" cubby, that has to be removed to gain access to the back of the fuel filler, was not a viable option considering the 8 degree Fahrenheit temperature in my garage on Saturday night.

 

That's where I put mine, plus it has a cover over it to keep it from the elements (at least more so than the open bay as there are holes in the cubby).

T@co_Pr3runn3r- Mine did not release or take in any pressure and I did mine in the cold though. If may have been taking air in as stated before since it let air out when hot (driving).

 

I did mine cold, not after driving.

 

What I was saying is that as you drive, it got hot. So it let air out the one way valve. Since it is one way, it did not let air back in. Then since you did the mod cold, the air inside the diff condensed, making the pressure inside the diff less than outside pressure (since it would have equalized when hot by pushing air out the one way valve). When you opened the valve, air goes in in order to equalize pressure.

If not, then I don't have a clue.

 

so i'm a total newb and I want to do this. It looks easy enough with the great instructions, pics, and walk through.

My question is, should I do this mod in the cold (air temp), when the truck is cold (air and havn't driven the truck) or warm (air temp) or when the truck is warm (been driven)?

Thanks...but then again, this is a "dad" truck so i probably don't even need to do it. But why not, right?

 

doesn't matter.

 

air temp makes not difference at all.

 

impulse and manwithoutaplan, thanks.

 

Doesn't matter. When you remove the OEM breather from the diff it will allow air in or out. Just be sure it's not too hot to the touch!! And that nothing falls in the diff!!

 

As he said, doesn't make a difference in the air temp.
Just ensure you aren't handling a hot differential, that wouldn't affect it - just would suck.

 

$7 Toyota 90930-03136 Toyota Breather Plug - 90930-03136

Toyota 90930-03136: 5/16” Barb
Toyota 90930-03031: M10 x 1.00 Thread Pitch

$7 Toyota 90404-51319 Toyota Genuine Parts - Union (90404-51319)

Toyota 90404-51319: M10 x 1.00 Thread Pitch, 3/8” Barb

$9 Toyota 90404-51026 Intake Air Control Valve Union

Toyota 90404-51026: M10 x 1.00 Thread Pitch, 1/4” Barb