Erikk120 Great pointer... Yes I had a friend go under the truck as I jumped on the rear bumper. I also got under the truck and pushed it up and down with my legs. I found the shocks were squeaky doing that. Good excuse to upgrade to 5100 bilsteins
I too thought could have been the bushings. I looked at replacing however, felt they would be easy enough to inspect. So I took off all the rear control arms and pan hard bar. All bushings were cleaned with dish soap, then denatured alcohol so as to be perfectly clean. After I treated them with AT 205 reseal (awesome product) and let set for a day so that could soak in. They were very carefully inspected for stress marks on the bushings and nothing was found. Lastly I applied high temp brake grease to the shafts the bolts go through... and properly pre-loaded the bushings w/ suspension loaded and truck level. I did the same with reconditioning the spring seats and shocks. (awesome technique for anything plastic or rubber on your vehicles).
I actually may have inadvertently discovered something when I changed out my perfectly fine u-joints... I had to use the truck for what I bought it for this weekend after completing the u-joints. That is going on forest roads through the snow and mud. D&mn fun I might add. I got back onto the pavement and realized my squeak was COMPLETELY gone.
The squeak slowly came back after driving another ten minutes or so on pavement. I couldn't for the life of me figure out what that might have been. Then I realized, the transmission yoke...
My guess right now is when the driveshaft was pressed in it distributed some of that grease to the splines in the yoke, stopping my squeak. However, after driving a little ways, the squeak came back because the grease worked it's way out of the yoke.
I had packed the transmission yoke with grease when I put the driveshaft back on.
I am thinking the yoke may not be well lubricated. I was also surprised when pulling the yoke off that no transmission fluid came out at all. Shouldn't the yoke get some transmission fluid or grease? When I rebuilt my Camaro Trany fluid came out after pulling off the driveshaft. So was surprised nothing came out here.
Any thoughts?