Squeeky Silverado

I have a 2005 Silverado, 90,000 miles. It started a squeak that seems to come from directly underneath the truck.This happens any time it is moving forward. I have ruled out belts and brakes as it is not coming from the engine or wheels. It seems to even make a slight noise if idling, but it is not consistent. I first thought it was coming from the front end, but when I listen from outside it is clearly coming from the center and under the truck.

If anyone has any ideas I would appreciate it.

Does this truck have a carrier bearing? That would be a bearing holding up the rear of the forward part of a two-part driveshaft. Either this or a U-joint would be my first guess.

It is likely to be one of the universal joints - more so than the carrier bearing. I have had to replace all three on my truck. The middle one seems to go first, then the rear, and much later the one right after the tranny.