Do the spherical bearings/uniballs on your beam also make a creaking noise? Mine should be self lubricating, but that doesn't seem to work well. If put some grease between the ball joint, after which the noise is gone, but it comes back in quite a short while. I guess it's pushing the grease out again because of the force on the ball joint.

Am I using the wrong grease, or the wrong ball joints? Or should it not turn on the ball joint, but on the sleeve going through the ball joint?