More on leaking axle seals and vents

[arrabil]

So as some of you may remember I vented my front axle after getting concerned about all the blown seals on the 42/43/4400 models. Here is an update....

When it hit 104 degrees I was about to get on the tractor and noticed a puddle. I traced it to the axle vent I made. At first I thought something I did went bad. When I opened the hood I found the answer.... the fluid expanded up the tube and out the vent. Thats three feet of hose it expanded out of!

When I built the vent, the fluid level was where it was supposed to be. That was April, 70 degrees tops. The fluid is Deere J20D hydraulic fluid just like in the rest of the tractor. I checked the rear viewport near the PTO and that fluid had also expanded way above normal (past the viewport).

I think this does explain why there is so much pressure in the axle as to blow out seals.

Not sure what to do at this point... I drained the excess fluid in the meantime but that just means I'll need to add more in the winter. Hmmm. Ideas?

 

[jimgerken]

Wow, that's a lot of expansion. Are you fairly sure the level was correct in April? The dipstick is short, but seems to suggest the level would be an inch and a half below the threads, or so. Can you post a link to your original thread please?

 

[nmu98]

Thats a ton of expansion for oil. Might you have your vent below the airspace in the axle? If you crack open your fill plug where you vented, does the oil go back down?

I don't buy that JD engineered these with next to zero space for expansion.

 

[Spudland_Dave]

I don't buy that JD engineered these with next to zero space for expansion.

Same here...sounds like you have a "dip tube" which is below the fluid level... the front axle is not 100% completely filled with oil...
Another thing that leads me to this conclusion is the fact that while yes, oil does expand & contract...it does not expand/contract as much as air...

 

[arrabil]

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]

I think the coolant expansion tank on my X475 is the right size for fitting under the hood. I'm going to investigate that option shortly.

 

[Spudland_Dave]

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

Just to muddy the water a little.....
IF you do build an expansion tank....when working on a side hill the fluid will just end up in your expansion tank...yeah, thats what its for, but fluid in the expansion tank = fluid not lubricating critical components, such as the pinion...you essentially are running it low. With a sealed box, when working on a side hill, the fluid is still 100% in the housing and is probably still lubricating the pinion.

Anybody have a JD Front end made of Clear Acrylic or Lexan so we can test my theories :laughing:

You guys had my brain whirring & humming this AM...now the more I think about it, I think I'll just keep it the way it left JD.

 

[nmu98]

Just to muddy the water a little.....
IF you do build an expansion tank....when working on a side hill the fluid will just end up in your expansion tank...yeah, thats what its for, but fluid in the expansion tank = fluid not lubricating critical components, such as the pinion...you essentially are running it low. With a sealed box, when working on a side hill, the fluid is still 100% in the housing and is probably still lubricating the pinion.

Anybody have a JD Front end made of Clear Acrylic or Lexan so we can test my theories :laughing:

You guys had my brain whirring & humming this AM...now the more I think about it, I think I'll just keep it the way it left JD.

:laughing: I just posted about the same thing in the other thread about this... Its almost scary....:thumbsup:

 

[arrabil]

SpudlandDave, point noted but I don't think enough fluid escapes the axle to qualify for running it low. 7.4qts in that tiny axle is an awful lot of fluid. And half a quart is the max I think would escape based on what happened earlier. The wheel hubs are always going to be full and the ring and pinion should not have any lubrication problems considering the speeds we're running.

I think the big problem is what nmu98 came up with in the other thread....

 

[dfkrug]

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.

I went back and read the original thread....it has been 3 months.

You hit on the cause. Once you got oil in your vent hose, the air behind it
expanded a lot. Surface tension will not allow the oil to drain back into the
axle very quickly on its own, so tipping the axle back the other way does
not allow the hot air to escape. Eventually, the axle cools off and sucks the
oil back in, but that does not help you much.

I think your venting scheme will only work if you have TWO vents, one
on each side. These Dana-Spicer axles don't have two fill ports, like some
other tractors have.