Help identifying fill point

[Andy JH]

Pretty sure all these little Chinese tractors are similar, even my old Kubota had the Transmission/ rear axel fill point located as per the photo.
But what has me stumped is what this fill point is for. It opens into the housing for the High Low gear shifter so I was wondering if someone knew?
Tractor is a Lhuzong 404A Compact, 4WD.

 

[piper184]

That is probably a vent. Have you had the plug out to see if it has a filter on the inside and a small hole somewhere?
The Jinma 284 that I have uses an inverted "U" pipe as a vent on that particular casting boss. It is a little more to the left where yours is centered but it is definitely a vent, yours probably is too, although a better design than the open tube I have. The other thing about the tube is it sticks up enough that I hit it with my right foot every time I get on and off the tractor. Maybe I should make a vent plug like yours for my tractor.
If you take it off, post a picture of the underside, I would like to see how it is made.

 

[Andy JH]

That is probably a vent. Have you had the plug out to see if it has a filter on the inside and a small hole somewhere?

It is a solid plug, no vent hole. Internally you can see the selector shaft and oil. No filter.
The transmission vent is located behind the seat.

 

[piper184]

That is interesting. On my tractor the vent behind the seat is for the hydraulics tank which is part of the 3 point lift assembly and what the seat frame actually bolts to.
Is the oil level under the plug at the level as the transmission oil on the dipstick?
In other words are you looking all the way down to the transmission oil level or is it a separate chamber? You could use a piece of wire and do a crude measurement to figure out if the oil is in the chamber or below it.
Dang, now I am curious and will probably have to go out and take the breather off of mine and look inside!

 

[LouNY]

Is it a retainer for the shaft?

 

[piper184]

Just checked my Jinma. Pulled the vent tube and couldn't see much down inside the cover. Put a straight piece of wire in it and it went all the way to the bottom of the transmission housing.
It would appear that the shaft for the low range is held in that boss. If it has a fork that extends down into the transmission it would seem that there has to be a hole from the cover to the transmission in which case the cover won't hold any oil on its own. That way the fork and shaft are probably just oiled by splash from the transmission gears.
If that boss is sealed and holds its own oil supply you could probably put about any kind of lube in there. 80W-90 or whatever you use in the transmission should work just fine.

 

[npalen]

Access port for an adjustment or disassembly?

 

[Andy JH]

Is the oil level under the plug at the level as the transmission oil on the dipstick?

No, this is why I am asking, the transmission oil level is a lot lower and when drained had no effect on the oil level in this compartment.

That way the fork and shaft are probably just oiled by splash from the transmission gears.

Starting to think this might be the answer

Access port for an adjustment or disassembly?

Possibly.

 

[piper184]

In the absence of a good parts diagram about all that is left is take it apart to see how it works.
The other side of that coin is "don't fix what ain't broke"
If you do take it apart, it would be nice to see pictures.

 

[Andy JH]

Think I might just cehck that there is oil in there from time to time.
Thanks for the replies