Front diff breather has large box? (1 Viewer)

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Joined
Oct 26, 2005
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1,161
Location
Farmington, NM
Hello,

Working towards extending my diff breathers (prior to axle rebuilds) and was looking at the front stock breather. I've read I think all of the "extend your breather" posts and all mention the stock breather (the spring, rubber gasket, one way valve with the metal top) but none have mentioned this large black box just below it that is mounted. The tube goes from the axle to the box with the valve on top.

Just wondering what the extra box is for? The rear is just the valve and my 4-runner just has the valve as well.

Second, I've seen talk of using Dino oil in the diffs so you will change it more often if you are in water. Is this overkill, since, I just put the breather higher to avoid water in the diff? I like syns but as mentioned if it will get tainted anyhow might as well save the money and go Dino.

Thanks,

TR
 
the box has been talked about in past threads, it is not present in earlier 80 series. it is just an empty box, I think it may be an air/oil seperator but truely the pourpose is unknown, I deleted it when extended my breathers.
 
My 97 has this too. When I extended my breathers, I checked the box over for damage and reinstalled above the DS fender near the battery. Its been like this for years with no problems.
 
Thanks guys,

I'll just get rid of it when I do the extend. I'm going with a cheap fuel filter inline and not running the back to the front.

TR
 
I left the box in place and extended the breather from the top of the box up to the ABS actuator. It is a seporator of sorts and I wanted to keep it in the loop.
 
cruiserdan said:
I left the box in place and extended the breather from the top of the box up to the ABS actuator. It is a seporator of sorts and I wanted to keep it in the loop.

Will do Cdan.

TR
 
I figured that the box is on the front because the front diff tends to get contaminated with grease from the knuckles. The grease contamination causes the gear oil to foam. I guess that the box is intended to be a space for the foam to collapse instead of flowing out of the breather valve. In other words, a hack.
 
I ran the rear breather up to the front, removed the box, Teed the rear and front, and used the modified rear valve up by the ABS. I have never seen oil or foam or anything come out of the modified valve.

-B-
 
TroutRunner said:
Second, I've seen talk of using Dino oil in the diffs so you will change it more often if you are in water. Is this overkill, since, I just put the breather higher to avoid water in the diff? I like syns but as mentioned if it will get tainted anyhow might as well save the money and go Dino.

TroutRunner,

You're joking, right? High water in New Mexico? Where are you wheelin'? :D

I use M1 in the diffs and if we ever see enough water to get in the diffs then I would change it with Dino, flush for a few days, then go back to M1.

-B-
 
i brought the rear to the front separately. left the box on for the front but it now sits under the hood
 
Beowulf said:
TroutRunner,

You're joking, right? High water in New Mexico? Where are you wheelin'? :D

I use M1 in the diffs and if we ever see enough water to get in the diffs then I would change it with Dino, flush for a few days, then go back to M1.

-B-

Oh yeah, I forgot. I plan to never leave the state. Well...I might go to Colorado on occasion. I think I remember some water up there.:D

Perhaps, we should modify our trucks to handle large fires?

Thanks B,

TR
 
Mine has the snork in case my wife backs the boat in the lake a wee bit too far.
 
When you guys Tee the front/rear and Tcase together (or any combo), be sure to use a large hose. Since you're adding so much length to the whole thing and now have a single point of air entry, using the same size hose that fit well over the oem axle nipple is not sufficient IMHO. Perhaps use a 1/2" hose and then step it down to each nipple?
 
the rate of air movement in and out of these cases is very low, all we are letting it do is expand and contract as it warms and cools. also air has a vely low viscosity, small hoses work well for air, 1/4 all the way through is fine.

I did a test with mine shortly after install I puled the drain plug on the rear with the fill still in place (I did test the fill to make sure it would come loose) the fluid ran out just fine without sucking air in, before extending the breathers because of the flapper valve it would glug like a gallon of milk turned upside down.

that shows the breather can handle near a gallon of air in in a short period. plenty.
 

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