Hi there,
The following is the information from GM as to how to test your shocks.
These shocks are NOT like the newer magnetic F55 shocks, so you may use this.
Personally, the control module for the F45 will set a code if the speed of the suspension overrides the shock and its not working effectively.
Stroke shocks by hand at various rates of speed. Stroke selective ride shocks at different rates of resistance by manually rotating the selector gear on the top of the shock.
Observe the resistance.
Rebound offers more resistance than compression (approximately 2 to 1). The resistance should be smooth and constant.
Compare with a known good shock.
A hissing noise is normal.
The following are considered abnormal and reason for replacement:
- A skip or a lag at reversal near mid-stroke.
- A seize (except at either extreme end of travel).
- A noise such as a grunt or a squeal after completing one full stroke in both directions.
- A fluid leak
- A clicking noise at fast reversal.
Allthebest, c4c5