John Deere 620 3 Point Operation

[Hawk Driver]

I have a JD 620 and the 3 pt operates okay with no weight on it, but put a few hundered pounds on it and it will take hi rpm to raise. Lowers just fine and hold itself well when tractor is off, even with weight on it. Hyd levels and pressurs are okay and the hyd remotes work okay (I have a JD 45 loader on the tractor and plenty of lift capacity with it). Is there an adjustment to correct this, or am I looking at a hyd relief valve issue?
 

[fixerupper]

I'm scratching my head pretty hard on this because it's been awhile since I've messed with the hydraulics on my 630, which is the same as a 620. Seems to me if the hydraulic lever for the remotes is in the forward position the three point won't go up. If the remote hydraulic is set for single acting the remote lever will not kick back when pushed forward and will stay there until you return it to neutral. When it's in neutral or in the raise (back) position the three point will go up. I'm thinking out loud here again, but I wonder if there's a connection between the two. Is your remote cylinder lever in the forward position? I haven't been into the valving for the three point for a good thirty years and I remember very little about it. Jim