just droped

i have 04 silverado.I just dropped my truck and i did the back end and now when u drive it makes a squeaking sound but when you bounce on the back end it doesnt make the noise so what do you think can be making this noise? I have a feeling its the driveshaft. Do you think it can be the pinion angle?

How did you lower the back???

belltech shackle and hanger kit 4"

check your shackles.make sure they arent to tight.theyll sqeek if theryre to tight sometimes.or the rubber bushing might be rubbing on the hanger itself,iv seen that happen too..but check the shackles loosen them up tad bit and put lil grease on them to help it out some