Front axle pressurized?

[mjonesnh]

Checked the fluid level a couple days ago on my TC34DA and when I unscrewed the dipstick there was a definite sound of pressure being released. This is the first time I can remember this sound when the dipstick has been removed. The fluid level was up to the full mark but not beyond it, tractor parked in shed so not in direct sunlight. Tractor had not been used for over a week so I am at a loss for an explanation. Anyone else ever notice this on their 4WD New Hollands?

 

[jinman]

Yes, I've noticed it on my TC45D when I check the front axle level after using the tractor for awhile, especially when it is hot out. I think it's normal.

 

[emorris]

My tc30 also does it when I check the fluid after I use it

 

[Redgoatea]

I just checked the fluid in my JD 870 yesterday and in did the same thing. Hope somebody knows the answer cause I don't. 7

 

[PILOON]

Sounds to me that there is no breather tube.
That, or if one is instaled, it is plugged up.

Plugged tube could cause seals to blow out.
Often a ball check valve thingy, or spring loaded relief device.

My tractor uses a tube that terminates near top of the radiator (so as to not ingest water).

 

[Gods Country]

Must be normal. My CCY 2400 does the same.

 

[jinman]

This is an example of why it is so important to fill only to the full mark on the dipstick and not all the way to the top. If you have no air space in the front axle housing, something will blow when it heats up.

 

[ovrszd]

I just checked the fluid in my JD 870 yesterday and in did the same thing. Hope somebody knows the answer cause I don't. 7

My Son's JD doesn't have a vent. He's replaced seals twice. It still starts leaking after a few hours of hot work. Remove the cap and it releases a lot of pressure. Poor design. All gearboxes should be vented.

 

[SPYDERLK]

There are sintered teflon vents that will allow gas to go thru but block water. There are also designs that allow breathing but exclude water by gravity.
larry

 

[OrangeRidge]

If you open the cap when the fluid is hot ( air escapes ) and then
replace it again , the air pressure will not be above atmospheric
again . Don't open when cold or it sucks in air again