Hydraulic Lift Issues, To-30

Posting because my grandfather is having issues with his TO-30 tractor.

He bought the tractor about 2 years ago. It has always had to "warm up" the hydraulic/transmission before his lift arms would work very well. If it didnt run for about 10-15 minutes prior to using it, the lift arms wouldnt raise at all. We live in southern Oklahoma, so its not a cold weather issue. Im not sure exactly what type of oil it had in it. But its a strong little tractor regardless of the lift issues.

Until Saturday everything had been working well just letting it warm up. He was dragging the pond trying to get some dirt moved around and the lift arms just stopped raising suddenly. He said it didnt make a noise, pop or crack at all. It just stopped.

I took the side plate off and drained the fluid from it today. About half a cup of water drained out first then all the oil. Not too badly considering he hasnt even checked it in the past 2 years and doesnt even know when the last time it was changed. It looks like it has some motor oil in it, and its pretty thick. So that is my thinking for the needing it to warm up and thin down so the pump can pick it up.

After it finished draining and I looked into the side plate where the dipstick is at, I could see about a half inch or so of sludge in the pan and on the bottom. Im in the process of cleaning it out with a 5 gallon bucket of diesel now and a little pressure sprayer. Its working well.

What do I need to look at to see if there is a pump problem, or even if there is an internal hydraulic/oil filter on it. Can someone give me an idea on where to start looking?

Thanks in advance!

In the first picture the two arms in the middle right go down to the control valve that is the "T" on the bottom of second picture. Occasional the T can come off the arms or the cotter pin that hold the "T" attached wears out and comes off. The worst case is if the valve breaks.

Reach down from the side cover and feel if it had come off the arms orpin is out. Both have happened to me. If it just came off the arms remove one of the side bolts on the arm and you will be able to spread to put it back in. If cotter pin out you can get at it from the large drain plug underneath.

The 15w-40 motor oil is a popular replacement for those tractors.

The TO-30 has the aluminum bridge that holds the legs of the control fork together. The control valve doesn't pop out like they will sometimes on the TO,TE-20's. With that being said the TO-30 came with the oscillating type control valve. They have been known to come apart after many years. With exposure to water and stuff for who knows how long I would say the original control valve is pitted. If it was me I would drop the pump and clean it out really good and get a new TO-20 style control valve ,(which will work fine in a TO-30 btw..) and then refill the hydraulics with your choice of SAE 90 mineral oil which is available at TSC and Napa or 10w30 engine oil. Either will work fine in your mild climate.

Thank you everyone!

I will let you know how it goes!