I am also putting the suspension back in. I took it apart almost a year ago and failed to take enough pictures. So this weekend I could not get the upper ball joints to fit right. A Haynes manual and even a factory service manual showed the ball joint going on top of the arm. I tried for hours and there is no way that would work on my truck. I remounted a joint on the underside of the arm for a test and it suddenly worked. I watched some youtube videos and saw k2500 and k3500 trucks with it going both ways, so I'm confident that putting it under the arm is right for my truck. It's annoying that even the factory service manual doesn't mention it.