Diff Breather Manifold (1 Viewer)

[Tools R Us]

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To me it just seems that cross contamination for something that is going to be up THAT high is really very low. If this was going to be mounted say on the framerail and then the intake tube ran up into the air canister I could see this potentially happening. But to run an air manifold way up high, then for any system to be able to push ANY liquid with enough pressure to even make it up to the highest point in the engine compartment just seems really low.

The"mechanism" that pushes the fluid up is pretty simple. When water gets into a gear box, the fluid level is raised by the amount of water introduced, higher oil level causes more oil foaming. Due to the gears spinning, water and oil do mix, emulsify into a thick mayonnaise like milkshake. This thick fluid doesn't flow well, so traps lots of air, add the air/foam volume and soon the whole gear box is full of foam. Water and air don't lube well, so the unit runs much hotter than normal. The heat doesn't have much effect on water and oil, but the air expands, causing pressure that is vented through the breather, taking the foam with it.

Yes I have seen mayonnaise milkshake blowing out breathers and have cross contaminated gear boxes, so I don't plumb them together anymore and damn sure wouldn't plumb gear boxes to electronics.

 

[Tools R Us]

Er why is there an issue with condensation if the stock breathers let in air (moist or dry)?

The stock "breathers" are one way valves, in theory they allow air out, but not in. At first glance this looks good, in real life, not so much. As the gear box warms, the air in it expands, the excess goes out the breather, when it cools the breather closes and if the housing was totally sealed there would be a vacuum. In real life no gear boxes are totally sealed and air is drawn in through the seals, etc.

Seals are designed to work one way, in most cases to keep oil in the box. Outside pressure can easily drive air, water, etc past them. With the stock setup, water is most often pulled in by vacuum. The rig has been driven, the box is at temp and submerged, this rapidly cools the box and air in it, it contracts, causing a vacuum that pulls the water in through the seals, etc.

By going to a free flow system some of this shortcoming is eliminated, but the fact is that most any stock automotive gear box is going to get some water in it when submerged. Most of the time, with short submerging, it's in small amounts that will be evaporated out with normal heat/cool breathing. But say that your crossing and the motor floods, or you get stuck, etc, now the box is setting submerged until the issue can be corrected.

How many have you wheeled with that climb under the rig and remove the fill plugs to check for contamination after each water crossing or even at the end of the day? Why would you, I have a breather system, have crossed deeper water before, etc, the point is that most times you don't know that a box is flooded. So it's a highway trip home, then you notice the fluid on the ground or check the fluid level and find the box full of mayonnaise.

The most effective way of "sealing" gear boxes is pressurizing them with air during a crossing, for most it's not worth the hassle. If you have seen one working, it's a good way show how much they leak, bubbles everywhere.

 

[WarDamnEagle]

No more moist air will enter the extensions than would enter the stock breathers.

-Spike

Spike, practically speaking, you are probably correct. However, thermodynamically there is a difference and it's two fold. Firstly, the more volume you add to a system, the more condensation you will have (on an absolute basis). To further explain, the entire system will come to equilibrium with a certain humidity and when the temperature cools then the moisture will condense. I know that the manifold tubing doesn't add much length to the system but that's not really where I was coming from.

For me the more interesting issue is the following. When the diff heats up with a stock diff, then the entire air space in the diff gets heated and most of the moisture will vaporize and some will escape with the air that leaves the diff. Yes, some air will come back in when they cool down and this will bring in some humidity (depending of course on temperature and humidity on the day) but, over time, the diffs will tend to stay pretty dry.

With a manifold, something a bit different happens. The manifold will never come up to the same temperature as the diff so when the humidity in the diff enters the manifold line, the manifold will act as a partial condenser and condense out the vapor. Some will run back into the diff and some will stay in the line (e.g. low points or even long flat runs). Over time there will probably be water in the lines unless you live in the Southwest.

Do I really think this is a problem? No, but it was late last night when I made the first post and just wanted to clarify what was going through my tired brain....

 

[-Spike-]

WarDamnEagle: gotcha.

-Spike

 

[NLXTACY]

I am just running 3 'Y' connectors in the lines to go from 4 into 1. The rear diff breather runs from the diff, up the chassis toward the front of the vehicle. As it passes the transfer there is a Y to join the transfer breather, then further forward another Y to join in the gearbox breather. Lastly the front diff breather joins it as it goes up the firewall to a cheapo fuel filter. Easy! I've used fuel line for the breather hoses so it shouldn't be worried by oil etc.

Hmmm, after just reading George's diff write up for the dozenth time...I am curious to understand how the way he did it would be better than the way I am suggesting:
Diff & Gearbox breather extension

He has all of the breathers tee'd into each other. And SCOTTSHZJ80 is basically the same thing. So with the thinking of having a HIGH placement of an air manifold, why is this NOT better than George's or Scott's method.

I'm trying not to push on this too much. Its just that the more I read what people are doing the more I see that people are doing just what I am proposing...just not through an air manifold.

SPIKE I totally see your point and understand it. But I question the legitimacy of everyone else's solution when they are guilty of exactly the same thing. Is each just a ticking time bomb or is maybe one better over another? I don't know. But I "think" that high placement of an air manifold is a better solution.

 

[-Spike-]

LOL, just because several other people did it wrong doesn't make it right. You do what you feel is right, if you don't see a problem with it.

-Spike

 

[96r50]

I did mine al seperately, using new OEM breather valves with the rubber flap removed. The rear diff vents by the gas filler, and the trans/xfer/front diff are bundled together by the charcoal canister (all on individual lines)

 

[ScottsHZJ80]

LOL, just because several other people did it wrong doesn't make it right.

Fair call Spike.

Yes I have seen mayonnaise milkshake blowing out breathers and have cross contaminated gear boxes, so I don't plumb them together anymore and damn sure wouldn't plumb gear boxes to electronics.

I must admit I hadn't really thought too much about cross contamination.

I can appreciate the problem in theory but is it really much of a problem IF, note the IF, the breathers are allowing air back into the diffs and boxes? I realise seals really only work well in one direction, ie to keep oil in, but shouldn't seals in good condition do their job and cause the system to draw or expel air through the breathers, rather than sucking water, dirt, crap, etc., past the seals? I am running a fuel filter rather than the OEM flapper beasties on the end of the breather tube for exactly this reason.

The electronics issue isn't relevant to me as I don't have any on my 1HZ However, if I did I would think long and hard before even risking getting oil and/or water in them. Yeah, I know that goes against the rest of what I just said.

 

[NLXTACY]

Well I "thought" about running the electronic breathers to them as well but I'm not going to go THAT nuts. But the other four (diffs, transfer, trans) I will. I think what I am going on is that this something that is directly linked to the FAQs, MANY people have already done it this way (or the individual fuel filter way) without any harm to speak of. So what I am looking at is to improve on the system that is already in play for those that have combined the lines. For those that use fuel filters and everything goes its separate direction thats fine. This isn't for those people. But if you are using a "Y" or if you are using a "T" fitting then using a HIGHER placed manifold makes more sense.

As PHOTOMAN said on a PM, could also add a dessicant filter as well!

 

[Mirage]

e lockers

I have factory e lcokers on my 97, do these have breathers as well or do i just need to run lines to the front and rear diffs. Also where are the tranny and tc breathers located.

thanks,

 

[Tools R Us]

I have factory e lcokers on my 97, do these have breathers as well or do i just need to run lines to the front and rear diffs. Also where are the tranny and tc breathers located.

thanks,

Yes, the e-locker actuators have breathers.

 

[concretejungle]

why not run the cheap balloon breathers and be done with it?

 

[mkhilario]

How do you know your balloon is of sufficient volume?

No one seems concerned about airflow resistance of long lines and manifolds. I don't pretend to know the airflow requirements but I would like minimal resistance that a short individual breather line offers.

After you assemble your single outlet octopus manifold, try blow through it from the rear diff hose end and check the resistance.

 

[rhyary]

Now that I have new rear e-locker, I got interested in the longer breather thread.
I understand that for the diff breathers I can use 1/4" fuel hose.
But the e-locker breather hose is tiny and stiff kind of a hose. Where do I source a longer hose like that?

I will be going individual lines.
After reading few options, is there a consensus on how to terminate the breather and the other side of the axles/e-lockers

 

[Tools R Us]

Now that I have new rear e-locker, I got interested in the longer breather thread.
I understand that for the diff breathers I can use 1/4" fuel hose.
But the e-locker breather hose is tiny and stiff kind of a hose. Where do I source a longer hose like that?

I will be going individual lines.
After reading few options, is there a consensus on how to terminate the breather and the other side of the axles/e-lockers

I use vacuum line for the actuators. If your not sure on the size, snip the end of the plastic line off and use that to find hose that fits. I use plastic fuel filters on the diff and trans lines, leave the actuator lines open. If terminated inside of the rig, where it's relatively clean/dry there is probably little need for filters.

 

[NLXTACY]

Thread was closed and as the OP I guess I get to reopen it. I wanted to continue with the breather project here since I started it and never finished it. Since I will be doing a lift coming up shortly I will update this page for future generations

 

[rolliges]

Looking forward to the completion.

Hey, can you finish your under hood light install too.

Just saying....

 

[NLXTACY]

Looking forward to the completion.

Hey, can you finish your under hood light install too.

Just saying....

Yeah yeah yeah

I just need to figure out a clever way of installing the OEM switch.

 

[guzzla]

HAHA!!!
3 years later and you still haven't sorted out the breathers.

I guess we all get distracted at times...

 

[NLXTACY]

HAHA!!!
3 years later and you still haven't sorted out the breathers.

I guess we all get distracted at times...

Tell me about it. I didn't mention it here but when I finally did my birfs, my mechanic mentioned that water got into the axle and did its damage. I could have saved myself a headache. I did a small handful of water crossings, nothing deep, but deep enough to cover the axle.