so im not sure if this was answered but can someone with experience tell me the proper way to remove my leaf pack from my truck safely so i can take it apart and found out why my truck is making this annoying squeak i have diagnosed to be coming from my shackles. its a 2004 silverado 1500

 

i don't know if this is your problem or not but those trucks had a problem with the spring eye bolts freezing up with rust .you can put never seize on the bolts and it helps squeaks. what ever you do be safe and use jack stands ,only do one side at a time .
support the frame at the rear on the bumper if it is in good enough shape ,but i prefer ,use them on the frame at the rear .use a floor jack under the Axel near or on the u-bolt mount ,jack up the one side till you have some pressure off the spring ,
then work on removing the eye bolts ,when you get them out then remove the u-bolts a torch works good if you have one or a impact wrench .make sure you still have the hydraulic jack under it because it will jump when loose .