coming home from work today got caught in traffic down to 40mph was still in overdrive and locked up. i hit the overdrive lock out button and went to drive. stopped due to traffic turned overdrive back on and when we go to 40mph went into overdrive and then locked up. is this normal for stock allsion it has been doing this ever since i got the truck. seem strange to go into overdrive so slow when it does the engine is struggling to pull itself it even gets a slight vibration to it. this makes it hard to merge onto the interstate even with aggrasive throttling it still shifts into overdrive around 52 mph.