Diff breathers

James · Jul 20, 2023

I think I have read this thread, andI’m still unclear on something.
does anyone have experience of this type of pressure device, specifically of it not working?
I can see how it handles excess pressure, I’m not clear on how it helps when a hot diff hits cold water. But I can’t believe that ineos have failed to account for a ’normal’ offroad challenge, and protected the various geared boxes underneath adequately.

I can see how installing breathers is logical, but I’d like to think it’s unnecessary… is everyone being super cautious, or is this a known certainty to cause water ingress?

AnD3rew · Jul 20, 2023

James said:
I think I have read this thread, andI’m still unclear on something.
does anyone have experience of this type of pressure device, specifically of it not working?
I can see how it handles excess pressure, I’m not clear on how it helps when a hot diff hits cold water. But I can’t believe that ineos have failed to account for a ’normal’ offroad challenge, and protected the various geared boxes underneath adequately.

I can see how installing breathers is logical, but I’d like to think it’s unnecessary… is everyone being super cautious, or is this a known certainty to cause water ingress?

It’s a known issue, certainty may be going too far. The problem is that these types of one way valves are good at releasing pressure, but if you drive a hot diff and axle into cold water, the pressure is going to suddenly drop, this will slam the valve closed on the breather and stop any water getting in through the breather, all good, but now you effectively have a vacuum and it will try to equalise itself however it can and that is generally through axle seals etc. probably less of a problem when the vehicle is new, but as it ages and wears the more likely that will happen while in the water and then water in the oil leads to premature and excess wear and corrosion.

TheDocAUS · Jul 20, 2023

Diff breathers are needed for anyone involved in water crossings above the top of the diff. No such water crossing means no need for third party diff breathers. Otherwise you run the risk of serious damage to the diffs, transmission and transfer case.

The small cost of fitting third party diff breathers is a lot cheaper than fixing a diff, transmission or transfer case due to water contamination.

James · Jul 20, 2023

Thanks andrew and doc for your answers.
So the answer is I’m disappointed. I had hoped that there was a better logic to the low-pressure situation than relying on axle seals, which as you say are not likely to resist negative pressure for long. As you note diff breathers are not expensive tech, I would have expected Ineos to put them in, at very low cost on the line. Fiddly work afterwards.
I suppose there’s always the old landrover manual recommended approach (which everyone obviously observes) of stop before the crossing and wait for everything to cool. Just a quiet hour or so to build a fire and boil a billy. Ahh the serenity.

gkhaldi · Jul 20, 2023

ORSO said:
are we kidding? breathers on axle and not raised inside the hood?

I asked the question to one of the Ineos specialist when they did the tour in Belgium and he confirmed that the Trialmaster had diff breathers. If I remember correctly they were routed to the battery compartment under the rear seat but I’m not a 100% sure. On holidays without the Grenadier now (too much sw issues to take it) so I’ll have a look when I’m back to confirm.

AnD3rew · Jul 20, 2023

gkhaldi said:
I asked the question to one of the Ineos specialist when they did the tour in Belgium and he confirmed that the Trialmaster had diff breathers. If I remember correctly they were routed to the battery compartment under the rear seat but I’m not a 100% sure. On holidays without the Grenadier now (too much sw issues to take it) so I’ll have a look when I’m back to confirm.

I think we have pretty much confirmed that this is not the case

DCPU · Jul 20, 2023

Tom109 said:
This post above says the thread is G3/4 (M30x2).

No, that's not what it says.

I've found a name stamped on the Ineos breather, looked up the company, and found a visually similar item in their catalogue. Whether this is the item used on the Grenadier, or Ineos/Carraro have specified a bespoke one, remains to be seen.

DCPU · Jul 20, 2023

AnD3rew said:
It’s a known issue, certainty may be going too far. The problem is that these types of one way valves are good at releasing pressure, but if you drive a hot diff and axle into cold water, the pressure is going to suddenly drop, this will slam the valve closed on the breather and stop any water getting in through the breather, all good, but now you effectively have a vacuum and it will try to equalise itself however it can and that is generally through axle seals etc. probably less of a problem when the vehicle is new, but as it ages and wears the more likely that will happen while in the water and then water in the oil leads to premature and excess wear and corrosion.

I've certainly had water in my diff oil, as well as oil leaking out of my hub ends and steering swivels. It's almost part and parcel of running old Landrovers and the constant balancing of wallet against maintenance tasks.

So whilst I'm confident that it gets in under certain conditions, I've never read anything regarding the science of creating a vacuum in the axle. Can anyone quantify the pressure differential that a hot axle will have in cold water? Is it enough to draw water in? Does the depth and flow of the water have an impact?

Maybe Ineos/Carraro have done some calculations and designed axle seals that also help keep water out as well as oil in? It would be helpful to know the design philosophy (back to access to the technical documentation) before spending money solving problems that may not exist.

Shopkeep · Jul 20, 2023

DCPU said:
I've certainly had water in my diff oil, as well as oil leaking out of my hub ends and steering swivels. It's almost part and parcel of running old Landrovers and the constant balancing of wallet against maintenance tasks.

So whilst I'm confident that it gets in under certain conditions, I've never read anything regarding the science of creating a vacuum in the axle. Can anyone quantify the pressure differential that a hot axle will have in cold water? Is it enough to draw water in? Does the depth and flow of the water have an impact?

Maybe Ineos/Carraro have done some calculations and designed axle seals that also help keep water out as well as oil in? It would be helpful to know the design philosophy (back to access to the technical documentation) before spending money solving problems that may not exist.

The axle cases look reasonably heavy and thickly cast, maybe they dissipate heat better and the valve will suffice?

DCPU · Jul 20, 2023

Shopkeep said:
The axle cases look reasonably heavy and thickly cast, maybe they dissipate heat better and the valve will suffice?

I hadn't even thought of that element.

There certainly seems to be more mass in the axle, especially around the differential.

AnD3rew · Jul 20, 2023

DCPU said:
I've certainly had water in my diff oil, as well as oil leaking out of my hub ends and steering swivels. It's almost part and parcel of running old Landrovers and the constant balancing of wallet against maintenance tasks.

So whilst I'm confident that it gets in under certain conditions, I've never read anything regarding the science of creating a vacuum in the axle. Can anyone quantify the pressure differential that a hot axle will have in cold water? Is it enough to draw water in? Does the depth and flow of the water have an impact?

Maybe Ineos/Carraro have done some calculations and designed axle seals that also help keep water out as well as oil in? It would be helpful to know the design philosophy (back to access to the technical documentation) before spending money solving problems that may not exist.

Can’t tell you an equation, I don’t think water flow will have a huge impact it’s more the temperature differential, I guess in theory flowing water will be worse as the diff wont heat up the water and so the temperature differential won’t even out as quickly but in reality most of the time the vehicle will be moving anyway so doubt it is a significant facto, depth will be to a point, but once you have a significant portion of the axle and diff in the water it will start to cool and if axle seals are underwater then there is risk.

as I said earlier I would guess it is probably less of a risk when seals etc are new, but overtime as they wear and perish the risk is likely to increas.

Tazzieman · Jul 20, 2023

I presume (or am I being too presumptious) they have had experience with G wagens , given the number of engineers from that project?
Do the military G wagens have raised diff breathers ex factory?

AnD3rew · Jul 20, 2023

Tazzieman said:
I presume (or am I being too presumptious) they have had experience with G wagens , given the number of engineers from that project?
Do the military G wagens have raised diff breathers ex factory?

I could be wrong but I believe the G wagens, at least the working versions of them come standard with raised breathers.

DCPU · Jul 20, 2023

gkhaldi said:
I asked the question to one of the Ineos specialist when they did the tour in Belgium and he confirmed that the Trialmaster had diff breathers. If I remember correctly they were routed to the battery compartment under the rear seat but I’m not a 100% sure. On holidays without the Grenadier now (too much sw issues to take it) so I’ll have a look when I’m back to confirm.

The tubing you may have seen under the rear seat is, I believe, the washer tubing that goes from the front tank to the rear wiper:

TheDocAUS · Jul 20, 2023

Red Winch have confirmed to me via email, the winch supplied for the INEOS Grenadier does NOT have a breather. Thanks again to Red Winch.

FYI: some Red Winches have breathers that can be plumbed into third party diff breathers to raise the breather.

Tom109 · Jul 20, 2023

DCPU said:
No, that's not what it says.

I've found a name stamped on the Ineos breather, looked up the company, and found a visually similar item in their catalogue. Whether this is the item used on the Grenadier, or Ineos/Carraro have specified a bespoke one, remains to be seen.

Yes, it pretty much does say that!

DCPU · Jul 20, 2023

"And if it's a standard one from their range, it looks like this one:"

If, obviously has a different meaning in your language...

OzyGrenie · Jul 26, 2023

Does anyone know about breathers for the ZF transmission and the TREMEC transfer case?

James · Jul 26, 2023

DCPU said:
I hadn't even thought of that element.

There certainly seems to be more mass in the axle, especially around the differential.

It’s good question; I doubt there’s easy data, but the temp differentials are probably more of an issue in Australia/Africa than anywhere else. I’m going to guess that working the axles does not create undue heat, and that really hot ambient temps are likely to get a higher number, who knows, maybe working hard 50 over a hot highway? Water can be 0, but in a hot country unlikely to be much less than 15, still a decent drop. Maybe someone could take a stab at the pressure (volume) change for say 5 litre air volume experiencing 35 degree drop?
I’m looking forward to being too distracted by having the car to do this much conjecture…

Clark Kent · Aug 11, 2023

OzyGrenie said:
Does anyone know about breathers for the ZF transmission and the TREMEC transfer case?

This could be the transfer case breather. Front face of the transfer case up the top. Viewable from the left side of the vehicle looking up and rearwards.
Hose goes forward along the top of the transmission then up between the firewall and the back of the engine. Can't follow it to see where it terminates.

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