1) the intermet cast aluminum steering knuckle failed in my 2004 Pontiac gran prix at 26,000 miles. I recollect hitting 2 large potholes, one at about 20,000 miles, the second at 25500 miles and the knuckle broke after bumping a curb at a speed of 28 miles an hour at 26,000 miles. ) when the steering knuckle failed, the half shaft came out, the tie rod bent, the aluminum rim broke, and the mcpherson strut bent. Total cost for the repair was $3,500. I was lucky that I hit a curb at a low speed. I was able to still steer the vehicle. The failure mode I believe was impact, rather than fatigue, which could have occurred at 70 miles on an interstate. 3) GM would not take responsibility for the failure as it was due to collision with a curb. This vehicle was repaired at cost to the company that I work for.

- North Canton, OH, USA