Breather Extensions

If you are regularly doing water crossings, there is something we recommend putting on your vehicle upgrade list above a snorkel, and that is extended breather kits for critical drivetrain components.

From factory, your 4WD will be fitted with breather valves on your differentials, transmission and transfer case. As the drivetrain works hard offroad these heat up, increasing the internal pressure. The breather valves vent excess pressure to protect the integrity of the seals. When you submerge the drivetrain in mud or water, there can be a rapid cooling which decreases the internal pressure and can suck water inside the casing either through the breather valve or the seals. Suffice to say, water inside your differentials, transmission or transfer case is not a good outcome.

The factory breathers for the transmission and transfer case tend to be higher than the differential breather valves, which are commonly a one-way valve straight into the top of the differential with a breather hose up to the chassis; but check all four on your 4WD. An extended breather kit typically removes the one-way valve and runs a breather hose to high in the engine bay, allowing the drivetrain components to breath air from a cleaner and drier location. There are quite a few aftermarket extended breather kits available, usually specific to vehicle make and model, and varying to include just the diffs (for around $100) or all four critical components (up to around $200). They typically come with detailed installation instructions and can be a DIY job with basic tools.