Introduction

Jimny's axles and transfer box have small caps which serve as air breathers - allowing the air to come in if the oil inside cools (and contracts) rapidly (for example when the vehicle dips into deep mud or water). However, there is a risk of that mud or water coming inside through those breathers, fouling the oil and causing expensive damage.

Therefore, it is very advisable to install extended breathers at least on front and rear axles. The "extended breathers" are nothing more than rubber hoses! They are dead simple to install. Installing them on a transfer case is more complicated (the transfer case should be dismounted first), and there is a much lower risk that a water would get over it anyway.

Installing the breathers on the axles

To install extended axle breathers on the axles, just buy good quality rubber hose (approx 6-7 m of length) with internal diameter of 1/2", and a few good quality metal screw-tight straps for hoses.

Remove factory breather caps from the axle differential housings and put on the rubber hoses, and tighten the metal straps on the connection point.

Lay the hoses through the underbody, in the engine bay, up to the bonnet height, avoiding hot surfaces. You do not even strictly need a "T" hose connector for interconnecting the two axles, as each hose can go independently up to the top.

Tie the hoses here and there with plastic strap ties, and leave enough extra slack hose near the axles, because the axles move up and down during usage.

Also leave a bit extra hose length at the top, so that you can "curl" the tops of the hoses back down. This will prevent the ingress of water through the hoses in case when power washing the vehicle. It isn't a bad idea to stuff some very thin (breathable) cloth (like a band aid material) in the tops of the hoses, to prevent ingress of dirt and insects inside.

During usage, check the hoses now and then in case that they are starting to come off at the axle connection point (you DO NOT want them to separate as that will leave a gaping hole for anything to enter the axles).

It is also advisable to put some thin meshy cover on the top of the hoses in the engine bay, to prevent ingress of dirt or bugs (but still allow air to pass through).

Installing the breathers on transfer case

More on the specific solutions to be written later on ...

Installing the breathers on the gearbox

More on the specific solutions to be written later on ...