Free to a good home: Bilstein 5100 Struts x2

I'm guessing the coils have some type of casting flaw? Deformed in such a way that when they are compressed and extended they make that loud noise.

The 5100s, which are fine, no issues with them were replaced with OEM Hitachi struts. I was able to purchase 2 fairly new complete OEM strut assemblies.

 

OP, How fast you going in that vid?

 

5100s are designed to only be used with the Stock Springs. Aftermarket you're asking for trouble and it looks like you found it.

Bilstein B8 5100 (Ride Height Adjustable) shock absorbers are designed for trucks and SUVs with a front OE coilover style suspension. Multiple snap-ring grooves in the body allow for different spring seat positions, providing 0-3 inches of front lift with OE springs (depending on application). The monotube shock absorbers feature a 46mm digressive piston a with self-adjusting deflective disc valve setting. Bilstein B8 5100 (Ride Height Adjustable) shock absorbers provide increased wheel travel and improved handling. Utilizing a B8 5100 (Ride Height Adjustable) shock absorber is the easiest way to level out your vehicle.

https://www.bilstein.com/us/en/prod...75721964705164971&DriveId=5180767408557695164

 

The were installed with the OEM springs at the 0" ride height adjustment point.

 

No, the springs have been the source of the noise since day one. Both OEM struts were replaced at 1,500 milrs, the noise lived on. The second set of Hitachi struts were replaced with the 5100s, the noise lived on. Now that the new OEM Hitachi strut and coil assemblies have been installed the noise has been eradicated.