Hello All, looking for some ideas of what is going on with one of our farm trucks.

1997 single cab 1500 z71 with about 140,000 miles.

it has developed a rattle/clanking to what sounds like me high on the motor. It idles fine but as soon as you increase RPMs a little bit you can hear it start. And it gets louder and worse the higher the RPMs get. It’s not a rhythmic sound, it’s a rattle/clank like rocks in a metal can or coke cans rattling around, best I can describe it. Any ideas???

thanks!