I have to agree with both Rooster and Mr. Buddy about not being able to react fast enough to the overload system activating. I have put a fence post or two into my 485R (only when using my MacDon) and activated the overload system. Most to think that this type of protection system prevents slugging and damage. It doesn't, not suppose to. Think of it as a slip clutch. Once an object enters the threshing system, it is caught and the overload protection system prevents material from wedging in too tight to be unplugged. I do agree with Rooster when he said that dense objects are the only way to activate it. I have harvested some very weedy river bottom fields (morning glory, 10ft horse weeds and ditch weed aka "marijuana," etc.) and never caused the APS overload protection system to go off and that is operating at 4 + mph in both corn and beans. The system is great because the APS system is tough and it handle the two wooden fence posts I picked up.