Well my GT-5000 is less then a week old and has 2.2 hours on it. It has started somewhat of a rattle and I can not tell if it is coming fro the motor or the body. Usually starts once the motor is warmed up and running full throttle, does not seem to be there with a cold engine. (Which is pulling me away from body rattles). I have lifted the hood and taking it off so it is not that. If I decrease the speed it seems to either go away or is not as loud to the point so I can not hear it. I almost hate to say it but almost seems like a valve or something tapping or rattling. I have only ever had Briggs motors so that may be the way this is supposed to sound but, it is definitely different. I will be running it a lot this week to see if I can figure this out. I know very general description but has anyone experienced anything similar with their new one? I guess if I can not figure it out then I hope it gets worse and then call Sears so they can hear it!