I can't find the link where I am supposed to post a new thread, but since this is totally related to what I am experiencing on my 2355, and the last post was at the time my problem began, I hope no one minds my tacking on. It has 1,600 hours since new. I began experiencing hydraulic problems with the loader, which had previously happened because the fluid got a bit low due to a couple of worn out hoses and a leaking ram, which I had repaired. But after checking the fluid level (it was good) I resumed working and all seemed well again. Since it was a kind of pulsating pressure issue I assumed it was air in the lines.
Shortened story: drained fluid, changed element filter (old one looked good) and put in new fluid. Same issue, when driving tractor (mostly use it with a 10 foot flail mower) everything worked fine until I started using the loader a bit. Then the "shudder" began and the loader finally crawled to a stop. But after a couple minutes of rest, allowed to idle or just drive, even while mowing, loader would resume working. If I tried to run it long enough even the non-ram steering would also stop intermittently. JD dealer told me it might be the fluid recirculating pump. Basically a low pressure lift pump that keeps the main pump reservoir full. If so, I would need to split the tractor to get to it.
After consulting here and some utube videos I found there was an additional "pickup screen" in the lower case, which I was not aware of, and had never changed or cleaned. Well, after I redrained the sump and pulled the big filter housing so I could clear the hyd. lines and get to the large, inverse hex cap/cover and the one on the opposite side (which oddly takes a slightly smaller and less common allen size) I was able to push out the nylon screen, and it was obviously the cause of some blockage. (And yes, do I feel stupid for not knowing this was there!)
At any rate, it seems that it slowed down the supply of fluid enough that the supply tank above the main pump would run dry if the demand was too great. After cleaning it out and trying to get any remaining crud out of the lateral, transverse hole where it resides, putting all back together and refilling fluid, it ran just like new again. For about 2 weeks. Now it's doing the same thing, and my first instinct is that the filter has picked up some residual crud, and must therefore be removed once again.
But now after reading the rest of this thread I think I may also need to destroke the pump seat as explained above. I will also likely pull the screen out again to check and was now wondering about the possibility of pulling that without draining all the fluid. I know I'll probably loose some when I pull the caps, but will it completely drain? By all the photos and descriptions, it looks like the 2355 and 2555 have nearly identical layout as what the OP's tractor has, and for sure the pump.
And what about the proportioniing valve (below) that I learned about on the Green Tractor Talk forum? I remember seeing this housing when I was under there the second time (I've got turf tires, so its a bit lower). Can any or all of these be removed for cleaning without draining fluid? I know the main filter can be changed with the sump full, but the other pieces sit lower on the fluid case. Although not a big deal to drain it, I'd prefer not to since my tractor sits too low for 5 gallon bucket to fit under, and I'd rather not drain new fluid if I don't have to. Yet I don't want to get caught under there with gallons of fluid pouring out with no drain pan.
Last question, are there any other filters (hydraulic fluid) that I haven't mentioned? Like in the main fluid pump? The image below shows the type of pump I have, with the round passage that runs horizontally across the top, and seems to meet another vertical passage on the left (drivers?) side of the pump. It seems the vertical passage is the destroking feature mentioned in earlier posts. I do have an owners manual but it does not specify exactly what filters it should have or descriptively show where they are, due to model differences.
Thanks to anyone who has taken the time to read all of this, and I hope it may also help some one else.
