B7510 3pt won't drop while running

[Knute]

My 7510 has developed a problem with the 3pt hitch. Not always, but most of the time, the 3pt hitch won't drop while the tractor is running. The lever won't push forward to lower it, almost like it's under pressure. If I turn it off, pull back on the lever slightly to raise it, then I can drop it normally and it will usually work fine to raise and lower one, maybe two times, after restarting. The loader works normally, no problems with it.

I've tried turning the knob below the seat completely both directions, it made no difference.

Any ideas, or is the next stop a trip to the service department?

 

[easygo]

Will it drop as usual when the engine is not running?

 

[Knute]

Yes, as I said if I turn the tractor off the 3pt will will drop using the lever as usual, it's only when running that it won't. I haven't tried it without a load on, it had the problem a couple of times over the winter with a 6' blade on (plowing snow) but that went away on it's own, didn't need to shut down for it to resolve, and now with a 4' box blade it gets really hung up.