L4701 HST Leaking Hydraulic Fluid

[Aidan.ostrowski]

My L4701 HST with only 700 hours started leaking hydraulic fluid from the starter. The starter has a gasket that mounts it to the bell housing which makes me think that there is supposed to be hydraulic fluid in with the flywheel. But I am not sure. I split the tractor and replaced all gaskets and seals between the bell housing and the transmission hoping this would stop any fluid from getting into the bellhouse but when I fired it up same problem… any suggestions would be appreciated, primarily if I’m crazy for thinking there’s supposed to be hydraulic fluid in there.

 

[fried1765]

My L4701 HST with only 700 hours started leaking hydraulic fluid from the starter. The starter has a gasket that mounts it to the bell housing which makes me think that there is supposed to be hydraulic fluid in with the flywheel. But I am not sure. I split the tractor and replaced all gaskets and seals between the bell housing and the transmission hoping this would stop any fluid from getting into the bellhouse but when I fired it up same problem… any suggestions would be appreciated, primarily if I’m crazy for thinking there’s supposed to be hydraulic fluid in there.

Hate to say it but.......I think you are "crazy" .... for thinking that.

 

[TheOldHokie]

My L4701 HST with only 700 hours started leaking hydraulic fluid from the starter. The starter has a gasket that mounts it to the bell housing which makes me think that there is supposed to be hydraulic fluid in with the flywheel. But I am not sure. I split the tractor and replaced all gaskets and seals between the bell housing and the transmission hoping this would stop any fluid from getting into the bellhouse but when I fired it up same problem… any suggestions would be appreciated, primarily if I’m crazy for thinking there’s supposed to be hydraulic fluid in there.

My huess is its not leaking from the starter. I would be looking further up on the engine.

Dan

 

[whitetiger]

Hate to say it but.......I think you are "crazy" .... for thinking that.

There should not be any oil in the bellhousing at all.

 

[fried1765]

There should not be any oil in the bellhousing at all.

AGREED!

 

[Aidan.ostrowski]

My huess is its not leaking from the starter. I would be looking further up on the engine.

Dan

I thought that at first, but when I split the bell housing almost a quart of hydraulic oil spilled out

 

[Aidan.ostrowski]

There should not be any oil in the bellhousing at all.

Are there common failure spots or seals on these HST units?

 

[TheOldHokie]

Are there common failure spots or seals on these HST units?

Oil cooler lines.

Dan

 

[whitetiger]

Are there common failure spots or seals on these HST units?

It has to be leaking from the input shaft seal, the transmission front cover gasket, or the front axle propeller shaft seals.

 

[North Idaho Wolfman]

On the older models, front axle propeller shaft seals, are the most common.

 

[Aidan.ostrowski]

If the hydrostatic filter is clogged could that build excess pressure in the system forcing it to leak out?

 

[whitetiger]

If the hydrostatic filter is clogged could that build excess pressure in the system forcing it to leak out?

No!
The only thing that could create pressure to leak hydraulic oil into the bell housing is the breather for the trans-axle assembly being plugged. It is located next to the dipstick, below and to the Left of the seat.