rear lift on 5011 ,goes up but comes down to 20cm off the ground

hi guys the rear lift on the 5011 raises up high but does not stay . it drops down to about 20cm ( 8 inches) from the ground,the preselector is in the "P" postion.
For what I have to do ( blowing snow) this does not inconvience me, for the time being. I would like to know what is the cause, and how to fix, I have a cab on my zetor, the pomp for hydrolics is up front, infront of the motor, I believe, ( am not expert in tractors). Is there a pomp inside the transmission too?
Another thing the selector arm, at our feet, left hand side of the hot seat, says it has 4 positions. The first, is pomp, the second, is pto and pomp, and third, is neutral, and finally pto, for trailerdrive, when I put selector in neutral postion nothing seems to happen , I can still lift the rear of tractor. ( Smelly scraches his head )I have seen some posts where there is talk of this problem , the lift not staying up, please give details as to how to correct this what I have seen in posts is vague, unless job is very simple to do.

Thank you for your time.

I think you have the controls set to draft control. move the small lever D-M-P to postion P, position control.

By the way, your description is a bit vague too

Ok Renze,

I have the selector in the right position
as I did stated in the first line of my post

when I pust the inner circuit lever all the way toward the rear, it raises the rear hoist and will lift the snowblower up at least 2feet off the ground, but it doesnt stay ther it drops to 20cm from ground.

when sitting in the hot seat the "p" position is all the way to the rear?

Yes, i think so.. i'll check that, we never use the draft setting because it causes a very uneven ploughing depth with a blunt worn out plough at difficult ground that changes from ore banks to bright sand...

Smelly, not sure about the first part of your problem, but the second part of your post is how it should work. When the PTO selector is in neutral you can still lift or lower the rear end, but you won't have hydraulic power to the remotes. You said that you blow snow, so if your chute was hydraulic you would need to move the pto selector to the pto and pump selection (fully forward) to have drive to the auger and the chute.

ya I am blowing snow, the selector for blowing snow and being able to turn the chute hydrolicly, as I have, is postion 2 (pto and pomp). I have zeto 5011. position 1 is just the pomp, postion 3 nuetral and position 4 pto trailer drive.
I just want to know, when I raise the hoist to max postion up, it slowly drops down to about 20cm (7 inches) off the ground, takes about 30 seconds to do this. Is this normal or should it stay raised. higher that 20cm.

I have seen in some of the posts that there is some thing inside the transmission housing that has to be changed, some valve or some thing that is leaking, and that we have to remove the top of the transmission ,under the seat. I have a cab on my zetor,

What is the name of this device that needs fixing, I am not a mechanic, but I do know how to take things apart

Another question while I am here , I see a pomp for the hydrolics oil at the front of the of the tractor,near the radiator, two hoses go to the rear and enter the transmission housing .one of the hoses the larger one has a big filter with a little pressure gage on it, before it enters the transmissin howsing. If this is the case, does that mean that the pomp is always on , even if I put the 4 position pto shaft drive engagement lever in the neutral postion, I have seen in some of the posts here on web site, where on some models the hydrolic pomp is inside the transmission housing, being inside the housing, on theses models, does the pomp turn off if the pto shaft drive engagement lever selector is in the neutral position?
Just trying to figured out how the darn thing works
I have a shop tech nical manual but there is no reference to the pomp

ok new info from the zetor dealer on my lift problem, apparently on the linkage under the cab that connects to the lift control arm , there is a washer that needs to be tighten to creat friction, the lift will stay up . if it is loose the vibration of moving the tractor will slowly drop the hoist .