ArraynHi Sir! Sorry for the delay, I was trying to run the model this past days. So I managed to overcome the issue above by just clicking in Clear Generated Data from the Model and move on. Then I made the rocker (bell crank) of the spring and set all joints, but I'm receiving the same message. I already reviewed the model and all the joints to see if they match with reality and they are matching, so I don't have a clue what's going on. I also changed all the joints for FIXED just to see what would happen like you did and then I could run the model and I actually obtained some very reasonable results, but I think that by setting all the joints as FIXED my simulation would not represent the reality. Do you know if I can let the joints as FIXED to make a chassis torsional stifness analysis? Beside, I'm upploading my model as it is today if you wanna take a look, with the joints sets as I think they have to be set. Again, I really apreciate your help mr. Peter! Thank you very very much!nArrayn