tapping

My truck makes a prett loud tapping noise. It only does it once it is warmed up. I've done a lot of research on it and it sounds just like a stuck lifter but it's louder than most videos I've seen. And most everywhere I've read on lifters says that the noise starts right when fired up and goes away when warmed up. But my truck does the opposite. It takes about ten minutes after I fire it up to start tappinng. And it does this untill the transmission hits the last two gears. Then the noise is very faint. Untill I let off the Gas then it's right back it.