BREATHE EASY – ARB Diff Breathers

11th February, 2021
ARBOffRoadIcons0916_Patrol_0504_smaler 1096

So you’re getting ready to head off on a 4WD adventure. You’ve set up your vehicle to be an almighty off road machine. Bull bar? Check. Winch? Check. Air Locker? Check. And you’re a sucker for a good water crossing so, of course, you’ve fitted a snorkel. You know the cost of an engine rebuild and you’re not stupid. But have you thought of the cost of a diff rebuild? If preventing costly damage to your diff meant spending less than a family dinner cost and a couple of hours on a Sunday afternoon, why wouldn’t you?



ARB offers a breather kit that acts similarly to a snorkel for your differentials, gearbox and transfer case. The ARB Diff Breather Kit is primarily a hub that transfers air in and out of the critical vehicle components; the kit includes a length of air tubing that is run to a high point (usually under the vehicle’s bonnet) where it is most protected from dust and water ingress when drawing air back in.

Out of the box, the four-port ARB Diff Breather Kit can be connected to all four key components (front diff, rear diff, transfer case and gearbox) and comes with enough tubing and fixtures to connect to the most common application of two differentials. With a small amount of additional tubing and fixtures (sold separately), the one kit will also accommodate your transfer case and gearbox. The ARB Diff Breather Kit is affordable and extremely simple to install. A small investment for full peace of mind and protection for your pride and joy.

Part Number: 170112


Firstly, how do diff breathers work and why is your factory diff breather not up to the task? Driving results in your drivetrain create a lot of heat because of the friction caused by your diff gears. The air inside the diff housing, the gearbox and the transfer case heats up. Now, as you know, hot air expands and this causes pressure inside your diff casing. Luckily, you have a factory diff breather that allows this air to escape. Unfortunately, many factory diff breathers utilise a one-way valve and if it gets blocked with dirt or mud (which is surprisingly common), the pressure can become enough to force oil through the next weakest seal. Other common factory diff breathers have outlets that are simply too low and in an area where they are likely to ingest water and mud. Definitely not good.


But it gets worse. For most of us off road fanatics, there’s nothing better than a good water crossing. When your 4WD first hits that refreshingly cool water, your drivetrain is usually warm. As the drivetrain is submerged, the air cools and thus reduces in size. Physics tells us that the pressure inside the drivetrain will want to equalise so outside air will want to enter, often via the oil seals in the diff (as the factory diff breather only allows air to escape). However, if the diff is underwater, it won’t be air that enters but rather whatever your vehicle is currently submerged in. This usually results in your diff housing being full of a swampy mix of water, dirt and oil. This is bad news for your diffs and you’re looking at corrosion at best and fatal damage at worse.

Contact your local ARB dealer for pricing and availability.

blog image