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? 

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There is writing on it showing work was done it is around 200 hours ago. 

https://drive.google.com/file/d/1npLv0U30eRPhk4J6ipYgQLvTVkmpx6Op/view?usp=sharing" rel="nofollow - https://drive.google.com/file/d/1npLv0U30eRPhk4J6ipYgQLvTVkmpx6Op/view?usp=sharing

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I was excited to find this info because it showed that the tractor had around 300 hours put on it on it in over 10 years. The PS filter canister had 4-19 written on the side of it also. 

I have around 15 hours on it and put it to work and it worked fine the first day pulling a 200 bushel wagon and moving bales off the field. Looking at everything, I wonder if that was the first time it saw work in a few years, and it stirred stuff up in the tranny. 

Then the next day I use it I get the problem. When the o-ring tore the second time there was a small chunk we couldn't find. I am wondering if it is caught in the screen. 

I took the first o-ring that was torn into town at a JD place and got 2 o-rings that looked real close to the torn one. I am planning on going to the AGCO dealer (farther away) and get a true o-ring meant for it. Part of me is wondering if the o-ring I put in there isn't the correct size. 

I just fine it odd that a tractor that was well kept would not of had the transmission fluids changed often. I am still thinking I need to do some adjustments on the clutch and the idler spool.  kept  https://drive.google.com/file/d/1hVQFY6CVitz4yq_Zjvro3iACBpe2c3xE/view?usp=sharing" rel="nofollow - https://drive.google.com/file/d/1hVQFY6CVitz4yq_Zjvro3iACBpe2c3xE/view?usp=sharing

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https://drive.google.com/file/d/1QkjbewfhYJ6ls3gcAg4ZhC__6zLgDDj3/view?usp=sharing" rel="nofollow - https://drive.google.com/file/d/1QkjbewfhYJ6ls3gcAg4ZhC__6zLgDDj3/view?usp=sharing

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https://drive.google.com/file/d/1JpZfDNJQ1zZuIHGjHBUFEwaFV4J5DL7E/view?usp=sharing" rel="nofollow - https://drive.google.com/file/d/1JpZfDNJQ1zZuIHGjHBUFEwaFV4J5DL7E/view?usp=sharing

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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.  

Would the clutches slipping create the black oil or do you have better idea? The transmission dipstick was still clear before I dropped the oil which is still odd. 

Do anyone have an idea what I would expect to pay for a transmission overhaul on the tractor before I start calling around? Since it still drives and moves easily through the gears before I parked it, can I get by with just replacing the clutches? 

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. 

He mentioned that I should get 5000 to 6000 hours before work will be needed again. So at 100 hours a year, I should not have to worry about the transmission for awhile. 

For example my dad bought a 8070 and within a month ended up putting a new front end in it because the original was shot. 700 hours later and the tractor is doing great. 

I go to church with the Agco parts guy, and he seems to think we can get some parts for it or get them tracked down. According to the date and time it has had less than 300 hours in the last 12 years. If you look at date and time stamps in the picture it has indication that work has already been done to the rear end and maintenance has been kept up on it. 

It is certainly a possibility previous work has been done to the rear end, I see what looks like a date on the two speed shift cover on the rear end.  I also see what looks like the possibility of a black belly ring gear on your maroon belly tractor, all indications of previous work.  I would hope like heck IF the trans was previously worked on, the lower cover and filter screen would have been removed and cleaned, but it is possible the large items you found in there "could" have been overlooked, and are not from the current issue.

If I may, I will suggest right now, that the only thing I would source from AGCO is a seal kit, new clutch discs, and new shaft nuts........ALL other items I would find on my own from a reputable salvage yard, I know of at least one good one that has a lot of 70xx trans parts, and bearings I get straight from the manufacture, I.E. Timken or equivalent.

I wish I was in a different position at the moment, or I would come help you out, those trans are not the hard to work on if you have the right facilities and equipment to do the job.