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Transmission breathers ...

One of the easiest modifications to make to a Suzuki SJ is to fit breather pipes to the transfer box and differential housings. Breathers permit the air pressure in the case to equalise. This pressure build up is usually caused by heat from the gears. A  the warm air expands, it needs a means of escape, and this is achieved via the breathers, which can be found at the top of the casing.

With the Suzuki SJ being a 4x4, this is further complicated. Occaisionally the hot diff is subject to a water crossing. The temperature of the water will be colder than that of the diff, and the rapidly cooling air trapped in the diff will cause a partial vacuum. This resulting vacuum will suck water and mud into the diff, ruining the oil, and eventually the gears. Suzuki SJs come fitted with little spring capped valves that are sucked closed by the vacuum. However these get dirty within minutes of starting off-roading and usually fail. The best way around this is to fit a hose from the breather to a high point on the vehicle which will not get submerged in water.

Installation ...

Prise off the spring loaded caps on top of both differentials and the transfer case, using an old screwdriver. Now fit a 12.5mm pipe over the breathers. A garden hosepipe works weel for this, or alternatively, you could use any tubing. The transfer box is slightly more difficult as the breather is a slightly different size, but by placing the end of the tubing in boiling water, it will be softened enough to slide it over easily. Secure each breather pipe with a jubilee hose clip. Connect all the pipes together using "T" pieces, so that only one pipe comes forward to the engine bulkhead where it can be secured. As added protection, a fuel filter can be fitted to keep any dirt at bay. When fitting the breather tubes, remember to allow enough excess for the natural movenment of the axles.


If there is any chance that you may cross really deep water, it may be worth adding a breather to the gear box as well. The  gear box will have to be dropped to allow access to the breather. The gear box breather tube can be connected to all the other breathers and secured in a similar fashion. While you are fitting the breathers, it may be worth while to check that there is a rubber stopper fitted to the bell housing, and check that any other "holes" are sealed, for example the drainage slot on the bottom of the bell housing near the gearbox. This slot can be sealed with a strip of tape, and will stop water entering and drowning the clutch.