John deere 2440 hydraulics

I have a 2440 that has started having problems with the loader. The loader studders/chatters when raising for what is becoming increasing periods of time. This isn't completely uncommon if I haven't used the tractor in several weeks. I was told the check valve had a slow leak in the hydraulic tank above the pump.Typically in one or two cycles with the loader the chattering was over and loader worked great. In the last two weeks the studdering has worsened and takes much longer to resolve. Twenty minutes to and hour. The last three times I have used it I could eventually get it to work the loader like normal. Suddenly it would work like normal by letting the tractor idieling for an extended period of time or if I turn it off and restart after it had run for around an hour. Kinda odd that it finally resolves but certainly something is not right.
I appreciate any suggestions.
Thanks,
Chris

How long or # of hrs of operation since hyd filter was changed & sump screen checked/cleaned? Does your 2440 have options of hyd pto &/or hi-lo. If so check hyd functions with these options in both control positions. What type hyd valve controls loader(ind or scv)?

Your tractors hyd problem could be caused by stroke control valve in frt hyd pump not seating correctly or hyd filter relief valve stuck open. I don't remember check valve in frt reservoir ever being a hyd problem but there's always a 1st time for everything.

The hydraulic reserve tank above the front pump is pretty much open ended from the the fill port receiving oil from the oil cooler and the return line back to the transmission case .
The transmission pump pushes oil to the front pump , the oil cooler , to the reserve tank and then back to the transmission case .
When ever the front pump requires oil at its inlet . Oil is supplied from the transmission pump and if that is not enough . Oil from the reserve tank and oil cooler flows backwards by gravity to the front pumps inlet .
Problem is when hydraulic loads are high flow for extended periods of time from the SCV . As when using a loader , backhoe , log splitter , hydraulic motor etc . The front pump runs out of supply oil .
This is why a ported filter cover is required to return high flow hydraulic loads to.This eliminates the transmission pump being a bottle neck .
Problem is made worse if the transmission pump is worn , the screen is plugged , the filter is plugged or the transmission or PTO hydraulic clutch(s) or brake(s) are leaking .
Lets hope that the brake and/or clutch linings has not been broken down by moisture or the incorrect type of oil . If the transmission screen is plugged with friction material this is bad . If the screen and filter also contain metal , this is worse . The tractor is pretty much a right off .

I changed the filter and screen was cleaned about a year ago.
The tractor does have a hi-lo. The hi-lo is working fine and I have changed the position several times and it doesn't seem to change the loader function.

One other finding with the stroke control valve. Intermittently the tractor is difficult to start and working the steering wheel relieves that symptom. I believe that stroke control valve is responsible for that loading of the hydraulic system... Correct?

Thanks for the suggestions! Can the stroke relief valve be fixed without pulling the entire pump?

Thanks,
Chris

This loader has an independent hydraulic systre.

Can you post a photo of the RH side of the loader control valve? Stroke control valve seat can be difficult to R&R with hyd pump in tractor.

Have seen and repaired many with similar symptoms. It is easy to see if the rockshaft valve is leaking by looking through
the hydraulic oil filler to see if there is any oil stream or fog indicating a high pressure leak.