JD770 hydraulic problem

[Pilot]

Good little tractor, but there mus be an internal leak somewhere.

With a load in the bucket and on the 3pt the 3pt drops down, then it jumps back up to where it belongs. Hydraulic system makes noise when I'm moving bucket or 3pt. Even without a 3 pt. load, it doesn't seem like the bucket can lift a full load. After shut down, 3pt. slowly drops down and the bucket if off the ground tilts slowly down. Doesn't leak oil onto the ground.
Repair guys say it could be this or that, maybe something simple or maybe $1,000.
I'm not a hydraulics guy, but are there any simple places to look? Any good ideas?
Thanks.

 

[Jack Murdock]

I had a 770 do similar and it was a relief valve internally that had failed my local guy and I did it and it didn't cost more then 2-300 including the valve. Sorry I don't remember which valve it was I sold that tractor over 10 years ago.

 

[beenthere]

Pilot
Best would (IMO) be to get yourself a copy of the service tech manual. Worth the price if a DIY type.

Here is a schematic of the relief valve location.