5th Gen 4Runner Rear Differential Breather Kit Install & Review

A differential breather kit prevents water from entering your drivetrain during water crossings. It connects the rear axle, differentials, transmission, and transfer case to a higher point on your 4Runner using 6-8mm tubing. As these components heat up, they need to vent, and when they cool down, they create a vacuum, which could draw in cold water during crossings. This water can mix with drivetrain fluids, potentially damaging components like your E-Locker. Installing a breather kit is a cheap and effective way to avoid these issues, especially if you plan on driving through water.

Find it online: 

• ARB Breather: Check Price

Different Types of Breather Kits and DIY Kits

Breather kits are all similar, and many DIY parts can be found on off-road websites like 4x4parts.com. However, we chose a trusted, pre-packaged ARB kit designed for our models for convenience. This kit replaces the OE differential breather, which has a short one-way valve prone to fluid issues. Installing a breather kit helps prevent water from entering the differential, reducing potential problems. While some owners may not see the need for one, we highly recommend it if you plan on crossing creeks or rivers during your off-road adventures.

Rear Differential Breather Kit Installation

Tools for the Breather Kit Install:

• ARB Breather Install Kit (Part #170112)
• Phillips Screwdriver
• 14 mm or adjustable wrench
• Cordless Drill (if mounting with self-tapping screws included in kit)
• Pocket Knife/Utility Knife
• Wire Cutters

Install Time:

• 1 – 2 Hours

Whats In the Box?

• Anodized Aluminium Manifold
• 4 x BSP ports for breather lines
• 1 x NPT ports for air filter
• Air filter assembly
• 4 x push-in fittings
• 3 x BSP plugs for plugging unused ports
• 8m x 8mm polyethylene tubing
• 2 x self-tapping screws
• 25 x cable ties

Video Installation

1. Locate Diff Breather and Remove

Locate the differential breather. If you have a dirty 4Runner like mine, you probably want to clean around your breather as much as you can.

If you fail to clean the dirt around your breather, you may risk getting some dirt or debris inside your differential when you are installing the new breather.

2. Install New Diff Breather (Shark Bite)

Once you have wiped down the area around your breather, you can now remove the old diff breather and install the new shark bite. The shark bite is a fitting that comes with your ARB breather kit. The shark bit is the plastic piece that fits inside the fitting that bites down on the plastic tubing.

3. Insert Breather Hose

Once you have installed the shark bite fitting, you can shove the first end of your tubing into the shark bite. Just shove the tubing straight in. This whole process is pretty simple, just make sure to shove the tubing straight in and not at an angle. One thing to keep in mind here is a little pro tip:

NOTE: Keep enough slack in your first loop connected to the differential to make room for droop in your axle. If you fail to leave enough slack in your tubing, you risk pulling the tube out of the fitting at full flex or even partial flex. Make sure you leave enough room in the tubing line to make up for your axle flexing left and right.

4. Start Running Breather Hose

After installing the shark bite fitting to the differential, you can choose where to run the tubing. Options include mounting the ARB manifold and breather on the passenger side near the intake, near the battery, or even inside the cabin by the spare tire tools. We chose to mount the ARB manifold on the firewall next to our TRD intake, as we plan to install an onboard air system there in the future. The driver side is tighter, so we left space for the SPOD setup. Be sure to seal the tubing with blue painters tape to prevent debris from entering while running the tubing.

5. Where to Run Tubing?

6. Prepare Aluminium Manifold

Once you have found your chosen route to run your ARB Breather Tubing, you want to pull all of the slack out and up through whatever side of the engine you are mounting your ARB manifold on. In our case, we chose the passenger side.

• Pic 1. As you can see in the first image above, this is the remaining slack that we had coming out of the engine.
• Pic 2. In the second image, you can see exactly how we plugged up the ARB manifold. You want to plug three holes and install one shark bite fitting in the remaining opening.

7. Mounting Aluminium Manifold

Now, you need to mount your ARB manifold. You can do this by using the self-tapping screws that come in the box.

1. Start by choosing your location
2. Use a long nail or screw to tap the first hole with a hammer
3. Use a drill bit just under the size of the screws provided to drill a hole
4. Screw down your ARB manifold in the hole you just drilled
5. Level your ARB manifold and mark another hole and then rotate your manifold aside
6. Use your drill bit to drill another hole in the location you have tapped
7. Rotate Manifold back in place and screw down provided screw
8. Hand tighten into place

That’s it! This was the hardest part of the install but as long as you know how to use a drill, you are good to go. After you hand tighten your ARB manifold, you can cut off any excess tubing and insert the tubing into the shark bite fitting. Then, screw down the Air Filter Assembly (The plastic round part) and you are set.

8. Connect The Air Filter Assembly

Once you have screwed down your Air Filter Assembly (The plastic round part), you are finished.