7060 Power Shift Has Me Puzzled

I went to start it yesterday (Friday), and it worked great for around 5 minutes and then it wouldn't move. I checked the power shift filter and the oil around it was black, with microscopic specks of iron fillings. Yet when I pulled the dipstick to the oil under the seat it was fairly clear. 

I ended up changing the PS filter with one from AGCO, and everything was back to normal. I had corn stalk bales to get off the field on Friday, and I was shifting a lot in the low side. Once I shifted it to 6 gear and the rpms on the tractor went way down like the transmission brake was kicking in. I stepped in the clutch and drove it in 4th gear for a while. Eventually I got brave and tried it in 6th gear and it went fine. About an hour in using the tractor didn't want to move in any gear. I could shut the engine down and restart it within 15-20 second and it would run fine until I had to put it in reverse. It just stalled with the clutch out. I would shut the engine down and then start it up again and put it into reverse and it would work fine until I had to put it in reverse, and I would have to kill the engine and restart the process. There were a few times where it was a delayed reaction, but it would engage. I ended up parking it Friday.

I checked the transmission oil on Sat**day before I started it, and was again still normal hydraulic color, but a little on the dark side, and the low side of normal. I decided to add a little trans/hydraulic oil, and ended up over filling it a little and was going to drain some out when I got it out of the shop. I started it up and heard a whining sound coming from the PS valve body on the passenger side of the tractor. It started to drip oil from the valve body also. It was a very small amount, but this was a new leak. I also noticed the hose on the top of the PS canister (back right of the tractor) was whining. When I felt the top hose, you could feel it pulsing. 

I ended up taking the filter off again and the oil was again all black in the PS canister. I also noticed that rubber o ring seal was torn on plastic piece that sits on top of the PS filter. I thought this was odd because I just replaced the o-ring along with the filter because it was torn when I took the off the first time. So the rubber o-ring was torn again within 2 hours of use? I find that odd. 

Anyway I replaced the o-ring with another one, and the noise and the whining was instantly gone and everything worked great. We hauled manure and I only got two loads hauled before the whining in the PS valve body and the hose on the top of the PS filter came back. I parked it on Sat**day, and I have not looked at the PS filter to see if the o-ring in bad again. 

I won't be back to the farm until next weekend, and I am going to start with draining all the oil in the transmission and starting with a new filter (AGCO) and an o-ring again and see if that doesn't help.

My question is is there a suction screen somewhere on the PS transmission (not the filter in the canister) that might be getting plugged. It acts like it is not getting enough transmission fluids to drive the tractor. When I shut the tractor down, and then restart the tractor it works again which makes me think something in getting plugged, and the moment the pressure drops with the tractor off, the particles settle down. I am thinking new oil might help with the valves not sticking. I am also hoping to adjust the idler spool and the transmission brake and see if that doesn't help. I just haven't had the chance yet. The hose line to the Gerotor pump looks fine. 

Any reason why the transmission dipstick under the seat is not the dark colored oil coming from the filter canister? I am wondering if the clutches are slipping some creating the black color. Currently the clutch is almost completely out before the clutch engages maybe 80%. If I adjust the transmission brake wouldn't that also have some effect on the clutch engaging sooner? 

Any idea where that could have come from? Again it looks like they replaced the Gerotor pump because it is not the maroon belly color. Could it have failed and the pieces come from that.  

I think I would look into having this front bearing support checked for cracks in the threads as an early step in the decision process.