Originally Posted by autozen

... When you add weight to the back, the leveling valve moves and ports more fluid to the hyd cyls to raise the car.

Does the valve control each side independantly? If so then perhaps the valve may be a problem? If not then the strut or the spring seems to be the most likely candidate from a logical perspective.

When the car is level, the valve zeroes out and all the fluid is again put into a recycling stage. I don't suspect a sphere, because they are just shock absorbers since there are no shocks. I'll look for a diagram.

I'd guess that a sphere would still be pressurized with no gas in it and be harsh due to lack of compressability, hence the lean toward the strut or spring as the culprit causing the lean.

Peter