Outer Limits 4x4 Board

Hi Guys,

Are diff breathers necessary if you only occasionally go in water. I would say that out of the 15 times or so that I have been offroad, I have only been in water once, and that was about 1-1.5 foot deep.

I can imagine that if you are constantly reversing a boat into the water, or do water crossings every month or so you would need them, but would the oil get contaminated from just the occasional crossing. I wouldn't need to change the oil every time would I??

As I understand it, if you didn't have diff breathers at all, the seals in the alxe would be under pressure when the diff gets hot, because hot air expands. So if you then went thru water and the diff cooled rapidly, it would have a tendancy to suck water in.

So the diff breather is a way of equalising this pressure difference. Which is also the reason why you don't want the end of the breather in water when you do a crossing.

It is best practice to let things cool down a bit before doing a relatively deep crossing anyway.

A mate in a Cherokee had a small split in his breather and turned is front diff innards into a coffee-coloured soup after a weekend at Landcruiser Mountain Park.

5upaMav wrote:As I understand it, if you didn't have diff breathers at all, the seals in the alxe would be under pressure when the diff gets hot, because hot air expands. So if you then went thru water and the diff cooled rapidly, it would have a tendancy to suck water in.

So the diff breather is a way of equalising this pressure difference. Which is also the reason why you don't want the end of the breather in water when you do a crossing.

It is best practice to let things cool down a bit before doing a relatively deep crossing anyway.

A mate in a Cherokee had a small split in his breather and turned is front diff innards into a coffee-coloured soup after a weekend at Landcruiser Mountain Park.

sorry, I guess I should have said 'extended diff breathers' as all diffs have breathers dont they?

Toyota breathers use a rubber spring loaded valve at the end THROW IT AWAY.
and put on an extended line with a small petrol filter on the end.

Extended breatheres a re a good idea on ANY 4x4.

You never know if your going to get water over the highest part of the current breather.

Only takes a second for a gulp of water to get sucked in with dirte consequences to bearing and thrust faces esp if disolved dirt present.

Bazzle

go for them,

Because what you save in the off chance that you may have to pull them apart it's worth it just to fit them the first time. If i had my time over again I would of extended them on the front on the MQ form day one and like you i only went in a couple of times, but every time i changed the front oil it was filthy.

breathers are definatly a must.
U will not have to worry about water getting in and doing damage and they dont impare of affect anything under nieth so they may as well stay there. Extending them is just getting a longer piece of feul hose and attacthing it on the diff where the old one was and move the other end to a desired location.
You will then only need to be worried about ur diff if the body is under water

Besides the cost of a diff breather extension kit is a small insurance against the cost/result of a dirty/damaged diff full of water such as my mate's hilux diff centres which had spring loaded breathers and I had changed them as well as the oil in them.

Both diffs were full of 3.5 litres of 'liquid' each which consisted of 2.8 litres of oil and the rest.. u guessed right... WATER!!!.. (factory luxes run 2.8 litres of oil per diff)

So fitted new breathers and ran them up to the firewall.

Needless to say.. noisy gears have gone.. and the car runs like a charm.





This bucket above was out of the rear lux diff (a 4 litre ice cream carton)