07 Tahoe squeak in Rear Suspension

[JDLSuper55]

I bought a 07 Tahoe with 120K miles on it. Its has been lowered and wheels put on. I bought it from a guy I work with, so I know it was well taken care of. I have this annoying squeak and it always sounds like there is something loose. Anytime I go over a speed bump or just little dips I always hear it. I have taken it to a shop, but they didn't see anything wrong. The only thing I kind of think it would be is the LR shock. Any ideals or suggestions?

 

[rockenthebowtie]

Does it still have the spare tire on the hoist.. check to see if the spare tire is easily moved it might have slack in the hoist cable allowing the spare tire to rub making the rubber squeak along the under carriage and can also cause a rattle.. but for squeaks and rattles theres to many variables being that there is alot of metal on rubber when it comes to suspension you can also get a can of wet silicone spray to spray all around the rubber parts its not a fix but can help narrow it down to where the squeak may be coming from dont use wd40 that will make the rubber swelll and then you'll have more problems later on