Ken,
I have a 3510 with the same loader.
I have found a similar oddity that I was just blaming on myself. I have been moving and spreading a lot of gravel lately and when loading from the pile, it is very susceptible to "corner tippage." (If your bucket digs in a little more on one side, the far rear tire lifts. We just filled the tire with windshield washer fluid, so maybe not as bad now. /forums/images/graemlins/crazy.gif
Anyway, to reduce the unbalanced loads, I will often lift the bucket way up and roll it back and forth once or twice and spill forward any "extra" load. With 2a modified, a full bucket is ok, an overfull bucket is too much to maneuver on the slope.
When I finish rolling the bucket back all the way, then drop the bucket quickly, I found the bucket always seemed to be rolled forward slightly.
Two reasons I found so far:
1. The loader does not allow simultaneous operation of lift and roll (at least, not much). If you move it left (roll back) and down at the same time, the bucket always rolls in the direction of the load (bleed by?)
2. The loader does not have an autoleveler like our bigger equipment. Therefore, the bucket doesn't keep the load level when moving bucket up or down. Just don't expect it to is all /forums/images/graemlins/smirk.gif
I haven't tried to leave the bucket in the air with a load. Will have to give it a shot. If it is the same, maybe have to add the same valve that others have recommended for a hydraulic top tilt arm for 3ph. It works in both directions, but only when proper pressure is pushing it to do so.
Maybe some of the hydraulics experts here can shed more light on this one.
-JC