After doing a complete overhaul of the suspension, the rear shocks is making squeaking noise every time the car moves. It is so loud and serious and that even if the car is stationary, I can reproduce the sound by rocking the car up and down. I've found the source of the sound to be from the bottom of the new shocks. There seems to be metal to metal friction. Any Idea why? my new shocks are Boge Turbogas.