Diff & Gearbox breather extension
In my opinion Toyota has always made a half hearted attempt at providing diff/gbox breathers.
Even my Heep Herokee has the front diff breather terminating up on the firewall!
Ditto for my MQ patrol - what's up with Mr Toyota?
Anyhow, a few dollars worth of 1/4" ID line fuel line (the cheap low pressure stuff) and some t-pieces and P clamps will quickly provide peace of mind when crossing water more than ankle deep.
In addition on the 80 series Toyota (in their infinite wisdom) put a spring loaded flapper valve at the end of their front diff breather. On several 80's that I've helped install OME suspension on, when the diff end of the breather hose unplugged (when pushing the suspension down to remove/install new coils) a definite hiss of air rushing into the axle housing was heard. i.e. the axle housing was under partial vacuum. I'm sure this accentuates a) ingress of water past seals etc and b) migration of grease from the birfields into the axle/diff housing area - it certainly can't help!
On US spec 80's (at least on post 95's that I have experience in - and possibly all 80's), it is possible to connect front and rear diffs and auto and transfer box breathers into a single breather connection that is mounted high in the engine compartment. A by-product of the modification is that you can make the breathers at the diff ends a bit longer to allow for full droop of the axles without fear of the breather hoses popping off in the future.
Following are a few pictures showing how I routed the lines to connect all these units together.
This picture shows the new longer breather line connecting the front diff to a Tee piece that has the breather hose coming from the rear diff. Visible just below the Tee piece is one of the P clamps holding the new breather hose to the chassis rail. The original front breather hose and termination box (with the air valve that we will later recycle) is removed from the vehicle. Note the breather hose connecting to the front diff has a spiral to ensure sufficient extra hose to account for maximum axle droop.
This picture shows the two breather hoses coming from the Auto transmission and the Transfer box connecting to another Tee piece. These hoses originally terminated near the top of the Auto dip stick. They have been unplugged from there and Tee-d together with an extended breather hose so as to also be raised higher on the fender.
This picture shows the location that the Auto and Transfer Box breather hoses use to terminate. Even though they connect into the Auto dip stick the connection was only external, i.e. the metal tubes coming from the dip stick do not make internal connection to the dip stick tube. I suppose Toyota just figured it was a high enough place to terminate the breathers - pity they didn't terminate the front and rear diff breathers as high!
This picture shows the final placement of the relocated breather valve. The valve is from the front diff and has been carefully opened and the rubber flap and spring removed. The top cover was then placed back over the valve and gently re-crimped. Visible are more of the P-clamps holding the hose down to the body.
This picture shows the new breather hose running along the inside of the US/DS chassis rail. The slit tube tie wrapped to the breather hose contains several +12V wires running from an auxiliary fuse box near the battery to the rear of the vehicle. One +12V feed is used in the +12V outlet I put in the rear cargo area, the second is a 'spare' that will come in handy for something ;-) The vertical U-bolt on the left side of the picture clamps the middle outrigger of my slider to the chassis. The lower lines have been moved away from the chassis (to allow the U-bolt to fit between the chassis and the lines) with a spacer. The spacer is slightly visible under the P-clamp and line clamp (on the far right of the picture).
This picture shows the new breather hose for the rear diff. Ensure you leave sufficient slack in the hose to allow for maximum axle droop. By allowing the hose to take it's natural curve (from being shipped in a roll), you can allow for extra hose in a 'neat' and tidy fashion.