Fill Level for Tiller Chain Case

[Riddler]

I have a small NH 105A tiller. I'd like to know the fill level for the case on the side of tiller that houses the chain and sprockets that turn the tine shaft.

The plug at the top of the chain/sprocket cover has a description that implies that the cover should be filled to within 3/8" of the top. That would mean that the chain and both sprockets would operate completely immersed in gear oil.

At the sametime, about 1/4 of the way from the bottom of the cover there is another hole and plug, which at minimum serves as an oil drain for the cover. I am wondering whether I am supposed to fill the gear oil only to the level of the drain plug? At that level, only the bottom sprocket would be immersed in oil, but the chain would pick up plenty of oil as it pass through the oil bath at the bottom quarter of the chain/sprocket cover. Also, the oil it picks up would seem to be enough to adequately lubricate the top sprocket as the lubricated chain passes over it.

Sorry for the long description, but do I fill the cover up or just to the level of lower drain plug? Thanks.

 

[oldballs]

Your tiller description sounds the same as my Land Pride 50 inch tiller. Thus, the top plug is for adding lubricant to the chain drive. The bottom plug should allow the lubricant to run out just a bit when filled to proper level... ....assuming the tiller itself is "level"

On the other hand, your tiller might be quite different than mine..

 

[Qapla]

if the top plug is in the very top, straight up, you would fill it like we used to fill radiators - when you can see the fluid looking into the hole. If the top plug is "near the top" on an angle to the top or on the side, fill it like a "rear end" in a vehicle, till the fluid begins to run out the filler hole.

If they did not want the top gear and the chain to have a healthy dose of oil, they would not build the cover/tank to house that much oil.

 

[RickB]

The low plug is the level plug. No way that case would be filled to within 3/8" of the top.

 

[Fallon]

Filling it to the top would blow out all your seals when things warmed up & expanded.

As long as your gears can pick up & fling lube you'll generally be fine. Most gear cases want to be about half full, which is where they usually put the check plug.

 

[RickB]

Filling it to the top would blow out all your seals when things warmed up & expanded.

As long as your gears can pick up & fling lube you'll generally be fine. Most gear cases want to be about half full, which is where they usually put the check plug.

True, but a chain case typically is at a lower level than a gear case.

 

[ruffdog]

I agree ^^^ that the lower plug would be the fill level.

 

[Fallon]

True, but a chain case typically is at a lower level than a gear case.

True, but it's not a high precision system. The sprocket & chain will be flinging lube all over that case in under 1 revolution. This is one of those things that you'll be just fine as long as you are in the vague ballpark, no precision required.

The lower limit for level would be enough that the chain would get dunked at some point in its path & the upper fill limit would either be arbitrary or based on not submerging the shaft seal so it has less chance of leaking.

 

[RickB]

True, but it's not a high precision system. The sprocket & chain will be flinging lube all over that case in under 1 revolution. This is one of those things that you'll be just fine as long as you are in the vague ballpark, no precision required.

The lower limit for level would be enough that the chain would get dunked at some point in its path & the upper fill limit would either be arbitrary or based on not submerging the shaft seal so it has less chance of leaking.

Agree. The typical gearbox has shaft seals partially flooded; a chain case not.

 

[Qapla]

This comment "The oil level is checked by removing the pipe plug in the center of the rear cover the oil level cannot be above the bottom edge of the plug hole.", was included in post number 2 of this post on a thread right here on this forum.