What Are Diff Breathers and Why You Need Them

Differential Breathers: The Snorkel for Your Diff

So you want to take your rig out for a wild time? Hit some runs, squeeze down some trails, or even traverse a creek or two?

You’ve probably considered putting a snorkel on your rig, both for the street cred and functionality, but that isn’t the only mod needed for a water lovin’ truck. 

Diff breathers are the less flashy but equally important cousin of an engine snorkel. Your differential is a key component in your vehicle’s drivetrain. It controls how much torque your engine sends to each wheel. The last thing you want is to drown your diff!  

This is one of the first modifications I make on any vehicle I own intended for off-road use, especially when water is involved!

What are Diff Breathers?

Your differential comes fitted with factory breathers. These are usually one-way valves that work to release pressure from the diff. As your vehicle runs, the oil in your differential will heat up, causing the diff to expand and build a lot of pressure. 

If you were to drive a hot diff through a cold stream or puddle, it would cool rapidly, causing it to contract and create a vacuum inside.

Like a vacuum, your diff will create suction as it contracts. If your diff happens to be submerged when this suction occurs, water will be sucked in through any weak points, such as oil seals or the factory breather.

You can avoid this with an extended diff breather, which can save hundreds in potential repairs, and stave off any premature rusting or failures.

Where Do You Put Diff Breathers

Stock breathers are usually fitted too low on a vehicle to be safe from complete submersion. When it comes to installing aftermarket breathers, you want to find the highest point possible to ensure pressure ventilation will occur well above the water line. 

A common spot to mount your breathers is in the engine bay, usually against the firewall. Just remember to keep your lines clear of anything hot! 

Where you decide to mount your diff breathers will really depend on your vehicle. Instructions should be provided when you buy a diff breather kit. Keep reading for a full guide on how to install your breathers. 

How to Install a Diff Breather

Diff Breathers

Installing diff breathers is a relatively simple process, even for beginners. 

First, be sure to purchase a diff breather kit that fits your vehicle. There are many universal kits available, but always double-check that it will work for your make and model. 

You can also build your own breather kit with a union, around 6ft of hose (transmission oil cooler hose, fuel hose, or pressure tube will do), two hose clamps and zip ties. 

A diff breather kit will already include these parts, which will make the installation process simpler if you aren’t a seasoned grease monkey.

Common household tools, such as a spanner, allen key, and zip ties, are all you really need for the install. This makes fitting diff breathers a real breeze (pun intended). Instructions for installation, and any extra tools required, will vary based on which kit you pick up. 

The general guidelines for your diff breather installation:

  • Use your spanner to remove the factory breather from your rear diff. Keep the area clean and clear of debris, as you don’t want anything to get inside your diff! Insert one of the new diff breather ports into the rear differential. 
  • For the front diff, in most cases you’ll be inserting your new line into the existing factory line. Be extra careful when fitting your new hose into the factory line. Creating a solid seal is the goal here. Run your new line up the back wall of the engine bay. Again, be sure to stay clear of anything hot!
  • Once your new line is connected to the rear diff, run it up along the chassis. Look for any existing lines or wiring to guide the new line to the engine bay. This is where the zip ties will come in handy, connect the tube as you go.
  • Once in the engine bay, it is time to mount your diff breather manifold and connect the lines. 

Just like that, you’re done! You now have a safe and dry location for your diff breather, that is well away from any wet ‘n’ wild accidents.

How to Clean a Diff Breather

Diff Breathers

Like any of your mods, checking on the state of your diff breathers is a good idea from time to time. Whether you have extended breathers or stock, they should be kept clear and clean for that easy breezy flow.

A clogged diff breather can result in a host of issues, so it is important to check for clogs or dirt. Common problems associated with a clogged breather are leaking seals, usually pinion seals or axle seals.  

To check your diff breather for any clogs, use a wrench to remove the breather port. Once removed, attempt to blow some air through the breather. 

If you find there’s no air flow, grab a can of brake cleaner. Brake cleaner is a fantastic cleaner for many parts on your rig. Flush your breather with brake cleaner until you can get air flow through again. 

Conclusion

Diff breathers are a very simple install with multiple benefits.

If you truly want your rig to be able to go anywhere, then diff breathers are essential. For the time and cost associated with the installation, it really is a no-brainer. Diff breathers are a fantastic place to start when it comes to off-road modifications. 

While you may not get the street cred of a 6” lift and snorkel, with diff breathers you can save hundreds in repairs. What does hundreds in savings mean? More money for mods, to get you closer to that beastly rig of your dreams.

Happy trails!

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