Puzzled about hydraulics on my YM240D

[oksanaut]

My YM240D (l4) started dropping 3-point hitch recently. Following threads here and on ymowners, I already drained the hydraulic fluid and cleaned the filter. Filled her back up and things move a lot smoother but 3pt still drops when loaded with a box scraper (before it dropped when loaded with a small adult). Closing stop valve with hitch up prevents it from dropping so the lift cylinder is holding. Started down the "clean out things, replace o-rings" path now, but got stumped by what I saw under the seat. I can recognize the stop valve and cylinder head, but the rest is not familiar and I am not finding mentions of or similar looking items in service or parts books. Tractor came with factory FEL and controls.

Can someone help me identify this and troubleshoot?





Is this some kind of lever on the relief valve? What is it for?



When I pulled the hydraulic strainer, I found two gashes in the mesh. To me these look like they were caused by improper handling (I had the tractor hydraulics serviced about 5 operating hours ago, last year). And what should I be looking for to I find a replacement "new type" strainer (threaded rod with a nut holding the hydraulic strainer in place)?

 

[HoyeTractor]

I actually had one of those valves on the shelf for a long time. It came in a box with the same part number on it as the regular valves but was significantly different. It was JD green so I figured it was something different that Deere used.




You can just use the screen below. It comes with all of the parts to retrofit your style screen.
HYDRAULIC SCREEN ASSEMBLY -SALE: Yanmar Tractor Parts