While driving a GMC 3500 denali hd 4X4 equipped with the diesel engine and automatic transmission, with less than 90 miles on it, the rear adjustment bracket for the left side torsion bar broke and fell off the vehicle while going over a speed bump at less than 20mph. More specifically, the part mounts near or in the crossmember brace and is used to adjust the preload on the torsion bar. After the part broke and fell off the vehicle had a noticeable list to the left side. The part is a cast part that appears to have failed in overload (underdesigned) or due to high stress concentrations (poor fit/tolerance issues). At city speeds I wouldn't expect much more than what happened to me. However, at highway speeds with a loaded truck or towing a trailer, the failure could result in control issues and therefore, in my opinion, should be classified as a safety issue. The dealer took the vehicle back and had a non-GMC facility "rebuild" the front suspension. According to the dealer, GMC has had at least one other similar incident. I currently have the broken part and possibly the original part from the right hand side of the vehicle.

- Homer, AK, USA