Semi Truck Suspension Stabilizer Bar Bushings

Old bushings were wore out, I put these in, perfect fit. So far everything is good.

I've replaced the stabilizer bar bushings and immediately after that the suspension started making a horrible creaking noise when one side of the car goes higher than the other. (when there is a pressure on stabilizer bar). I've tried lubing them, but it only works for a couple of days, then the sound comes back. Everything was installed by the books and using the correct torque values. I've put the old original bushings back and the sound went away. Other people claim a difference between rubber and polyurethane bushings, but I cannot find the material they are made of in this website.