Venting the front axle on CUTs(with pics)

[Rob-D]

Ordinary vented gear cases on vehicles will allow water in if submerged.

How? It's physics. The outside pressure has to be greater than the inside pressure.

How many times are you driving with your front axle submerged? I've never had my front axle completely under water.
What kind of pressure are we talking about here? Remember you have seals that will let water by if the water pressure is greater than than the case pressure and the seals ability to prevent passage. Also remember we're talking about a .050" hole in my adapter but if you want to run a tube be my guest but now you have to find a way to also incorporate your dipstick along with the fact that you have an obtrusion.

Rob

 

[Rob-D]

My tractor has a vented transmission but the front axle is not vented!

That's exactly right and that's also the problem, pressure is pushing oil out the seals. Tha't what I'm addressing in my design.

Rob

 

[msmud]

Rob-D
What you suggest is interesting. I don't know if someone has already suggested it, but what would happen if you drilled a very small hole through the plastic as a permanent, open vent? How much dirt could really enter? Oil can be hygroscopic; a permanent vent might let in humidity that causes some corrosion.

Or, could owners just loosen the front axle cap for a few seconds after each use of the tractor such that the axle doesn't sit pressurized for a period of time? When is the oil leaking out, during the couple hours of use that heats up the oil, or afterwards during the several hours of cooldown?

I'm just wondering about the simplest approach here.
Tim

 

[nmu98]

Rob,
I do not know if you seen this, but this could be a flaw in the venting plan.

Original Thread Link
There are more pictures on page 5 too.

You'll have to trust me that the axle was properly filled because I checked it while I was making the vent. And I do all kinds of axle work so....

Looking back at the expansion situation... I was parked on a slope, vent side down. So the oil was pooled there and then it would make sense for the air in the axle to have pushed it out.

Look at the plug I made... I don't think it sticks into the axle excessively, do you? In fact I don't think it sticks into the axle more than one thread.

And while I would like to believe JD engineered these with lots of room for expansion, they didn't have to put all that much thought into it.... the axle is sealed by design.

Seems to me, working on a slope means you can't vent the axle unless you build in an expansion tank?

 

[arrabil]

but if you want to run a tube be my guest but now you have to find a way to also incorporate your dipstick along with the fact that you have an obtrusion.

I did exactly that. I pointed it out to you in April. You must have forgot.

Either way... the problem is air and oil expansion as reposted by nmu98 from the thread I started on the subject. I'm going to add an overflow container if I can find one small enough. Maybe from a motorcycle or a small Deere.

 

[Egon]

That's exactly right and that's also the problem, pressure is pushing oil out the seals.

Doesn't seem to be a problem for me!:thumbsup:

There are times the water will be above the axle.

How? It's physics. The outside pressure has to be greater than the inside pressure.

Very true. Vented case has no inside pressure. Height of water has pressure. Physics.:thumbsup:

 

[Egon]

Sounds lke you guys may want to invest in Party Barges & Boats instead of tractors...do you guys spend more time fording rivers then cutting grass?

Creek crossings, mud/water holes.:thumbsup:

 

[nmu98]

I did exactly that. I pointed it out to you in April. You must have forgot.

Either way... the problem is air and oil expansion as reposted by nmu98 from the thread I started on the subject. I'm going to add an overflow container if I can find one small enough. Maybe from a motorcycle or a small Deere.

I applaud you guys for working to solve a possible problem with the front axles. It sure seems that JD has sealed these for a reason. Possible due to the same problem that Arrabil has, getting fluid out his vent hose.

Now correct me if I am wrong on this. If you add a single vent hose and run it to a tank:
1. you cannot have any loops or low hanging bends in the line since oil would pool there and could stop oil from leaking back into the axle if it were looped enough. Kind of like what plumbers put under sinks (water trap)
2. with an expansion tank, IF you ran across a situation that pushed oil up into the tank while using it, the internal heating of air could for a pressure in the axle and could not allow the oil to drain back into the axle for some time. It would require a pressure drop or for the air to escape past the oil up the tube. A larger diameter tube would solve this issue. Would the amount of oil pushed up the tube have any negative consequence on the axle?

Might have Spicer or JD seen this problem with there engineering studies and said the axle is better off with a little air pressure or did they take the easy way out?

Might you be able to get a fairly vented yet mostly sealed axle by just removing the rubber o ring on the fill/dipstick? It should then allow air out when the pressure builds but keep the oil in. The question is what is stronger and tighter the seals or the cap without the o-ring.

I think this is great stuff, but if rob was cutting a hill side and pumped all the lube, or a lot of lube out his breather, that would suck a lot more than a possible seal leak. With no disrespect, we don't even know if the seals failing is due to no vent.:confused2:

 

[msmud]

For those who have had a problem with axle leakage, when do you notice the problem? Do you come back from the field with the axle dripping or the inner aspect of the front tires glistening with oil, or do you notice it later as a puddle under the machine?

With both my 3038E and my mom's 3320 Cab model (neither of which has had this problem), I notice that unscrewing the front axle dipstick can release pressure days after the last machine use. If increased internal air pressure over time causes oil seepage through the seals, then it seems to me releasing the axle pressure right after each tractor use might be a whole lot simpler than installing a vent, tube, and oil collection system under the hood.

 

[dk8019]

msmud, I've noticed the same thing. I suppose in time, as the seal wears it may not be able to contain the pressure build up, and would start leaking. The pressure build up on my only occurs after working it a bit, but it's there to be sure.