The Suzuki Jinmny is a very robust and well built car for off-road purposes. If you have plans to go a little deeper than the standard factory wading depth limits you should consider this inexpensive modification to prevent water from getting inside the gear wheels.

The differentials and the transfer case box from the Suzuki Jimny have breathers fitted with a one-way valve inside the cap. This valve made of a coil spring and a rubber disk has the purpose to relief the internal pressure from the heated box blocking the entrance of dirt and water. The gearbox has it's own factory installed breather extension without any valves on it.

When crossing a deep river (water lever higher than the half of the wheel) there is the risk of water and solids get inside the differentials contaminating the oil, accelerating the oxidation process and the wear of the gears and bearings. There are many theories for the water entrance, some claim that the valve is so efficient that when the differential is quickly cooled it generates an intense vacuum that sucks the water thru the rubber seals. Others believe that the combination of the rubber disk and the tiny coil spring can't provide enough sealing in the presence of mud or other solids.

This article shows how to extend the original breathers from the wheel level to the engine compartment level using materials found in most of the DIY shops. This measure costs about 20 USD (if installed correctly), takes about 2 hours of your time and can avoid very expensive repairs.

Although I particularly never had problems with water inside the gears of my brand new Jimny I decided to extend the breather as a preventive action. With the caps/valves I took out from the differentials I did some experiences that drove to the conclusion they are very efficient when new.

NOTE 1: Sorry about the muddy parts. The Jimny had just completed a trail before I took the pictures. It's normally cleaner that that.

NOTE 2: It is impossible to get the oil sucked from a differential to the other or from the differential to the transfer case using a single line of breather extensions.

Materials and tools

• Big pliers.
• Screwdriver.
• Piece of cloth for cleaning up the breather nipples.
• 6 meters of reinforced rubber hose (300psi rated). Internal diameter of 1/2 inch.
• 0.5 meter of reinforced rubber hose (300psi rated). Internal diameter of 1/4 inch.
• 1 meter of reinforced rubber hose (300psi rated). Internal diameter of 3/8 inch.
• Steel clamp for 1/2 inch hose.
• 3 "T" hose adapters with 1/2".
• 140mm length plastic lock straps .
• 1/2" to 3/8" hose reduction adapter *.
• 1/2" to 1/4" hose reduction adapter **.

* The 1/2" to 3/8" hose reduction adapter is not easy to find in some markets. Alternatively you can use 10mm external diameter pipe to fit both hoses.

** It is possible to fit the 1/4" hose inside the 1/2" hose. If you need lubrication use soap or glycerin since they don't attack the rubber.

Preventive maintenance

• Every time you replace the engine oil or lift the car, verify the clamps and possible damages to the hoses. Remember that without the check valves the whole system can be compromised in case of failure of one the pipes.
• To check if the hoses are properly connected and there are no leakages you can blow the end of the breather extension line. If the pressure increases everything is OK.

Step by step of the installation