QuestionQUESTION: Hi. I am having trouble figuring out the problem with our 1070 Case tractor. It is a 1972 with the powershift transmission, serial # 8680702, and has just over 8000 hours. I don't think the powershift has had any work done on it but the hydraulic pump was changed a few years ago.
When you let the clutch out, the front end loader is real slow in 1st and 2nd powershift for about 10 seconds, then speeds up to normal. It lifts good in 3rd.
Also if you try starting off with a load behind it slips for about 10 seconds then suddenly takes off.
I checked the pressures of all the ports on the valve body. C1, c2, c3, and c4 all eventually pressure up to 180-200 psi. Lube port is 65 psi. On c1 and c2 after letting out the clutch in 1st powershift the pressure slowly rises to about 125 psi in 10 seconds then suddenly rises to full pressure. In c3 the same thing happens when shifting down from 3rd to 2nd powershift.
I checked the pressures of the remote hydraulics and the same thing happened. The pressure slowly rises in 1st and 2nd to about 1000 psi in 10 seconds then rises to 1800 psi.
I took the top off the valve body and all the valve spools seemed free. I took the inching spool apart and the springs and tip look good.
I was told I should get a guage and flow rate the remote hydraulics but the loader lifts real fast even with a bale on after this 10 second delay.
Do you have any idea what the problem might be or know of any more tests that we should do?
Thanks.
ANSWER: Hello,
Doesn't sound like a pump problem if it lifts OK in 3rd powershift. There is probably a leak in the powershift that is taking too much oil away from the rest of the hydraulic system. C1 clutch is used in powershift 1 and 2, but is not used in powershift 3 or reverse, so there is likely a problem with C1. The C1 piston seal could be leaking until the pressure builds high enough that it finally pushes the seal out enough to stop leaking. It could also be worn sealing rings in the oil distributor behind the powershift unit. I would think that a blown powershift control valve gasket or blown o-ring on a jumper tube would cause low pressure all the time and not just for 10 seconds. Because there are 2 clutches engaged in each powershift, there is a tool that a Case IH dealer would have that can disable each pilot spool in the control valve separately so you can isolate the clutches. If you install this tool to stop oil from going to C1 and your problem goes away, then it would confirm that C1 has a leak. The tool is installed in place of the access plug for the C1 pilot spool. It is a plug with a short piece of metal rod attached to stop the pilot spool from moving, which would not allow any oil to C1 clutch. This is a fabricated tool, so it does not have a tool number.
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QUESTION: Can I put a solid peice of rod in place of the spring between the plug and the spool or does the oil have to flow through here?
ANSWER: Hello,
A solid piece should be OK. The tool that I saw was a plug with a shallow hole drilled part way into it, and then a piece of steel rod was driven into the hole to make it a permanent tool. You wouldn't have to attach the rod to the plug to use it temporarily. A piece that fits into the spool in place of the spring will work fine, but doesn't have to be as big in diameter as the spring. The rod that was used to make the tool was about 3/16", but unfortunately, I don't know the length. It would have to be the correct length so that it will hold the spool all the way in when the plug is screwed in.
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QUESTION: I put a piece of rod to hold the c1 spool closed and it stopped the problem. Pressure comes up right away now on c2 port after letting the clutch out. Is there any way to know if it is the c1 piston seals leaking, or the oil distributor rings? It looks like from the shop manual that I could change the c1 piston seals just by splitting the tractor at the engine. Would the powershift transmission have to be taken right out to change the oil distributor rings?
AnswerHello,
There is really no way to know exactly where the leak is until you pull it apart, but you have to split the tractor anyway so it doesn't matter. You can repair everything by splitting the tractor behind the engine. After splitting the tractor, remove the front cover inside the bell housing, remove the planetary gear carrier, and pull the clutch and drum assembly out. You can replace the the piston seals, clutch plates, and oil distributor rings all at one time.
