So I've starting looking into the breather mod.

The best write up i've found so far is actually for an FJ here: Breather Tubes - Toyota FJ Cruiser Forum

Parts:

• 3/8 Fuel hose: about 25ft (not verified yet)
• Small fuel filter (3/8
• Rear Diff Union Part # 90404-51319
• 4 way "T" fitting (brass)

I know there are other breathers on our vehicles:
- Rear axle
- Rear locker (??)
- Transmission (??)
- Transfer case? (??)

Does anyone have any details on those and what the hose size is?

Okki

im interested in this as well.

In a moment of miser / frugality I purchased the union fitting from the camry because it was less $. I'll look at the pn later. Saved a wopping $4 or so. I was not sure what the difference was between the two pn I had seen posted. I think it may be diameter of outlet but not sure. The one I bought needs 1/4" inner diameter fuel line not 3/8".

I first purchased 25' 3/8 line then 25' 1/4 fuel line from amz for less than $1 ft each time. Way cheaper than local stores, but buying the wrong line the first time destroyed my initial savings. On the bright side I now have a supply of fuel line, and I understand a necessary chemical to make fuel line is in short supply currently. Small victory....

I have not installed yet. In a complimentary project, I'll have to pull my BB diff skid to change the fluid and was too lazy to do it last weekend.

I don't understand why you are listing a 4-way brass fitting. The link you posted has a picture of a 3-way plastic .25x.25x1/8 fitting. This is further confirmation that the hose size is 1/4". The link also shows the e locker location and you can see it uses the 1/8" hose and will fit to the 3 way valve.

IMO .....I think you all are way over complicating this unless your planning on being a submarine captain.
The front diff has one raised already coming up on the left side of the engine and the tranny and gearbox has them raised up coming up behind the engine next to the firewall and they are about the height of the air intake.

You go in water deeper then that and water closing the breather check valve will be the least of your problems.

But you can go in water deeper then where the oem rear diff breather is and the reason for a mod raising it up. Not sure why they raised only 3 of the 4 breathers?I have mine running up along side the gas filler tube and ending right on the other side of the gas filler door. Just make sure to leave slack as the rear flexes alot. I think it was at 42" high so it will be fine as I hope I don't go in over my tires. I don't think I'd attempt to go in over my door bottoms really as they aren't water tight. There is alot of things that need waterproofed or relocated going in really deep water , like the ECU's.

Yeah.. I know some are already raised, but I saw a really nice breather mod on a Landrover where he combined all breathers into a single filter and I just thought it was cool

The link I have is for an FJ; not sure is the diameters for the 4Runner are the same; that's why I asked the question I also listed the 4 way because of combining ALL breathers and not just 2. I'll have to see if I bookmarked that landrover mod thread on my laptop.

Okki

Harper, are you saying then that the two breathers I see in the engine bay cover the diff, tcase and transmission?

Okay. checked with the local stealership.. they want $13 for the rear diff union!! So I stopped by Napa.. they were clueless as to what 1/8 NPT means, had no filters. I walked out... Napa is right around the corner from my house, but they reinforced today why I drive 5 miles to O'Reilly.

So much for getting the first pile of parts for this mod today.

Okki

Look up the part number at Toyota Parts - Genuine OEM Toyota Auto Parts and Accessories, I think I pieced mine out and it was like $9. But than shipping is like $13 cause I ordered a few other stuff so I don't know.

Toyota Union Fitting- #90404-51319
Toyota Breather Plug- # 90930-03136

Thought this might be helpful for people to have an idea what the parts look like.

Okki

$13 plus the other parts - maybe $30 total at the high end - is not expensive compared to turning your diff oil into a milkshake.