Two-Way Diff and T Case Breather MOD

I did my own version of the scuba breather mod based on these:

http://www.tacomaworld.com/forum/off-roading-trails/15093-scuba-mod-relocating-front-rear-diff-tranny-transfer-case-e-locker-breather.html

http://www.tacomaworld.com/forum/technical-chat/111954-my-differential-breather-mod-photos.html

Big thanks to both for locations and ideas.

I ran the rear differential and transmission breathers up to the engine bay right behind the battery and extended the two breathers that were already relocated up there just a little further.

Parts:
- Toyota Part #

$7 90404-51026 Intake Air Control Valve Union

90404-51026 (Camry Union Piece for Rear Diff)
- Specter Filters (Autozone/Advance Auto)
- 1/4" Fuel Line (little less than 15') and some hose clamps
- 1/8 x 1/4 x 1/4 'T' Barb Connector
- 3/8" x 1/4" Barb Connector

If you got an e-locker breather, your gonna need another 'T' to tie in the rear breather. I don't have one, so I can't give the info on that.

UPDATE: Before this mod, my diff oil had water in them after about 5k miles (or one hunting season). I just had a chance to check the fluid after this mod and it came out clean. I think another oil change after this hunting season will be enough evidence for me.

2ND UPDATE: 15k on this breather setup. Fluids still look like new. Filters look very clean too.

I also made a box out of a 4 gang electrical box from Lowes and used the breathers that Shadow-Warrior recommended (specter).

 

Believe other breather is for add actuator.

 

Did I miss any breathers? Is the T-Case and Transmission the same breather?

I followed the transmission breather line and it looks like it connects to two spots. One is the transmission, the other looks like it could be the t-case.

 

Looks clean, what are those filters you are using?

 

autozone

 

thats pretty badazz!

 

I was able to change the diff oil yesterday to check it and test the two-way breather theory.

Before, my diff oils had water in them after about 5k miles (or one hunting season with water crossings). But this time it came out clean, and I even went further and more diff dunking on this oil than the last.

So it looks like the two-way breather helps release pressure from expand also, probably helping keep water out. I think another oil change after this hunting season will be enough evidence for me.

 

L

 

Looks good! Might have to do this in addition to my rear diff relocate

 

When you say ADD, are you talking about the t-case... or something else?

 

Automatic Disconnect Differential

I didn't even know it had a breather until I started poking around.

 

I need to find a schematic of this.... i always thought the ADD components were inside the front diff...

 

so how many Toyota parts did you order?

2 unions? I did not see a parts list in the OP.

 

I updated it with a parts list.

 

Nice.

 

This is on a new 2014 OFF ROAD with about 3k miles. The truck was cold after sitting over night.

So, when I went to remove the factory vent on the rear diff, I noticed there was some air pressure releasing from the vent cap. I would guess there was something like 2 or 3 psi in the rear axle.

I then disassembled the breather fitting to find a spring and rubber washer inside.

It seems to me like this is a check valve but is also designed to hold a small amount of pressure in the axle to keep water and dust / mud out of the diff. It would also keep the seals lubricated and running true on the axles and pinion.

As a result of this, I did run a fuel line up to the cubby but I decided to re-use this factory vent fitting to maintain the factory pressure setting inside the diff.

I did purchase the 2 Toyota parts mentioned earlier but only used the nipple piece on the axle.

Any knowledge or comments on this are appreciated...

Has anybody else noticed this?

 

No no... the spring in the factory vent (breather) simply secures it closed to keep junk out when you are bouncing around. The thing is not a breather, however. It will not equalize pressure if you drop a hot diff into cold water... and that's how contamination of the diff with water happens.

We install the same breather that Toyota already puts on the front diff when we do the mod on the back... and up high so water, excess dust stays out.

I am not a Toyota Tech, so I will defer to one if there is error in my logic.
I drove in deep, muddy water when my truck was 6 months old, and the rear diff was contaminated. I did the breather mod (see the link in my sig) and 4 years of off roading since has never contaminated the fluid since.

Throw away the original factory rear 'breather', and do the mod correctly with the front breather or an aftermarket breather filter, up above any possible water crossing level.

 

I noticed some oil on my filter. anybody else see this? I highly doubt oil is traveling all the way from the rear diff to the engine compartment where I relocated the breather

 

What size filters are used here?