DIY - High level breathers for gearboxes
With all the in/out of my gearbox I decided to install some high-level breathers for some piece of mind with water crossings.
Very easy to do with some simple parts.
The gearbox breather is in a alluminium boss that is press-fit into the top of the box. The Alu boss is easily twisted out with vice grips and a screwdriver. I levered off the original breather and drilled out the hole slightly to accept a tap. I tapped and inserted a 1/8"BSPT to 5-16" 90deg brass fitting with some flange paste to seal it. Blue-max for the boss and tapped it back into the gearbox no worries.
The transfer box breather is in the gearstick shifter plate - I removed this and drilled the hole to 10mm before tapping to 1/4"BSPT, I ran a 1/4" to 1/8" reducer then another 1/8" BSPT 90deg to 5-16" brass elbow as there was nothing 5-16" 90deg in 1/4" at the shop. More flange paste and screwed it in nice and firm.
I ran 5-16" auto transmission cooler hose (oil stable) up and terminated the ends with more brass fittings,
I used a 5-16" to 1/8" for the gearbox as the breather is a female, and I used a 5-16" to 1/4" male as the transferbox breather will fit inside the 1/4" fitting with some epoxy.
Both are now cable-tied next to my clutch master cylinder until I work out a more secure clamping arangement.
Well worth the time next time you drop the gearbox.
*note: you can probably tap out the gearbox boss from below and re-insert it the same if you are careful so you _may_ be able to do this without removing the box BUT you would definitly need to remove the gearbox shifter up through the cab to tap it out to 1/4" due to shavings into the transfer box.
breathers
rear-axle one is right to the side of the diff - this one is next on my list to move, not sure where to though, it is a long route to the front of the vehicle and no easy cavity inside the rear quater but hose is cheap and I should not be lazy.
The entire front diff and front freewheel is breathed via the vaccume assy on the intake side of the engine bay - little black plastic 10mm dia thingie, this could be routed up higher BUT i'll probably use 10mm ID hose and not move the plastic thing as it appears to be a valve of some sort. I could hard-line it up but again I'm not really sure if it is under vaccume at some times.
NO do not link the breathers with a "T" - as I am re-using the original breathers there may not be enough flow and I have seen heaps of issues linking gearboxes to thransfer boxes/diffs etc with breathers - just not worth it.
Ultimately i'll get a 4-port block on the firewall where all 4 points can be breathed next to each other.
It's just a rubber cap
32905 is just a rubber cap, sitting on the top of a tube, with the vent line on the other end - I extended that all the way to the top near the brake booster.
The reason why I suggest raising the VSV assembly is that both VSV solenoids have vent caps and you can possibly suck water through them into the intake if the solenoids switch positions whilst submerged - as designed, one of the VSVs is open at all times and vacuum is applied through one set of the tubes, to the actuator diaphram whenever the engine is running - I rerouted the vacuum lines on my car so that vacuum is only applied when 2H is selected.
For what it's worth - as far as I know, there is no reason not to tee the breathers together - I've seen it done by several 4WD manufacturers - the SQ series Suzuki Grand Vitara comes with high level breathers from the factory - transfer case & transmission breathers tee together and end up high on the firewall just below the windscreen, the rear axle breather - you might like to try this Bob - ends up in the space behind the left rear lamp, and the front axle breather sits to the right of the radiator at bonnet level - this is the lowest of the three.
breathers
32905 is just a rubber cap, sitting on the top of a plastic tube, with the vent line on the other end - the reason why I suggest raising the VSV assembly is that both VSV solenoids have vent caps and you can possibly suck water through them into the intake if the solenoids switch positions whilst submerged.
For what it's worth - as far as I know, there is no reason not to tee the breathers together - I've seen it done by several 4WD manufacturers - the SQ series Suzuki Grand Vitara comes with high level breathers from the factory - transfer case & transmission breathers tee together and end up high on the firewall just below the windscreen, the rear axle breather - you might like to try this Bob - ends up in the space behind the left rear lamp, and the front axle breather sits to the right of the radiator at bonnet level - this is the lowest of the three.
No worries, I might do that this weekend then, move the solenoids up and add a breather to the front diff, My main issue in the past has been from breathers allowing oil transfer between boxes at angles and water contamination in one box fouling the other especially with gearboxes running hot and blowing water vapour out the breather.
behind the rear tail light sounds promising - just not sure if there is a cavity on the Io for that
Syndicate
Axles
You need to do the axles as well - the rear axle breather is directly on the axle, and the front is on the right frame rail where the freewheel VSVs are - as a matter of fact you need to extend the lines and move the VSV assembly higher or run the risk of sucking water into the intake.