Over the years I've got some very useful information on this forum and I'm hopeful someone might be able to shed some light on a recent issue with our 8010.  Over the weekend I was sowing wheat and after 39 years and 10k hours of operation the soft hose that goes from the main piston pump under the tractor to the valve body for the remotes rubbed thru.  It didn't blow and spray everywhere but it had a pretty good stream running out.  I caught it when I got out to check the drill,  but otherwise never noticed anything amiss with the operation of the tractor.  No noises or lack of hydraulic pressure.

I shut the tractor down and removed the old hose.  My local parts store was out of 3/4" hose so it ended up going overnight to the next afternoon when I could get a hose made.  After installing the hose and adding around 4.5 or 5 gallons of oil we started the tractor.  

Before the engine even fired,  I noticed a noise coming from the pump which I accounted to air in the system.  Well,  long story short the noise has not gone away.  It sounds like a blower or something running and the noise certainly seems to be coming from the piston pump.  When you move the remotes,  it shuts up for the most part but still doesn't sound quite right.  

We changed the hydraulic oil filter,  which wasn't even a year old as it got replaced at the beginning of hay making as it always does.  I don't have the maintenance log handy, but I'd guess it got changed in late April.  When we did that,  and started the tractor it sounded normal for maybe 30 seconds or so and then went back to making the noise.  It almost sounds like it under a lot of pressure.  The hydraulics seem to be working just as I would expect and no issues other than the noise are showing themselves.  

I can't think the pump ran dry as we only added at most 5 gallons to a 17 gallon system which I know was in the top sight glass when I started the day.  I'm really obsessive about checking that stuff before every day.  

Any insight would be massively appreciated.  Thank you.