Hi All,

I have had a rattle in my rear drivers side suspension for a few months now. It is starting to drive me insane. I have removed the rear wheel and tried to see if anything is loose, but nothing seems loose. The rear air shocks were replaced last fall (with Monroe MA822 Max-Air Air Shocks) and a compressor from the junk yard, so I do not suspect this to be the problem. All the bolts for the suspension were tightened down with a torque wrench to the proper torques, and I rechecked them again to make sure this wasn't the issue. The ELC system seems to be working properly, the car rides at the proper height and the compressor runs for 15-30 seconds or so each time you get in and go.

Today in an effort to further diagnose my problem I was bouncing the rear of the car up and down by putting my weight on it, but there was no rattle. Then I kicked the rear drivers side tire on the front and back side. Normally this would cause the car to just rock forward and backward, but instead the suspension made the noise and the tire seemed to rattle back and forth. I did this same test on the other side and the tire rattled less and made no noise. What would cause this to happen?

Jack that wheel off the ground by putting the jack under the car body, not the suspension. Now have a kick fit again and you might be able to find the rattle better.

Also, while the wheel is off the ground, grap the tire at the 9 and 3 oclock position and try to push/pull. Same thing with 12 and 6 oclock. Find any play?

Hi Mike,

I jacked the car up from the body and my findings were rather disappointing. There was no give at 9 and 3 o'clock and no give at 12 and 6 o'clock. When I tried kicking the tire, the rattle was gone. Interestingly if I lowered the jack just enough that the tire started to touch the ground and the vehicle'* weight began to return to the suspension, when I kicked the tire at the 9 o'clock and 3 o'clock position on the treads, the rattling sound slowly began to return.

If I kick the passengers side tire, I can hear the drivers side making the noise a little bit. I suspect the vibration from my kicking is being transmitted back through the stabilizer bar.

I am going to have to repeat the process with my Dad this weekend and see if between the two of us can't figure it out.

I looked at the shock mounts in to the trunk and they do not appear to be rotted or anything of that nature and the shock feels tight in them. How would one know if they were bad?

Any ideas what would cause a rattle, but no looseness? It definitely still sounds like it is something in the suspension.

Sway bar end links. A-arms. Could be a number of things. Yes, it would help if you had a second pair of eyes and ears to look for the rattle.

I have some ramps I can pull the car up on this weekend and give it a real good look. One person can shake the car while the other listens real close, hopefully this will lead me to my rattle. To be honest the past few months I almost had myself convinced it was something loose in the door, until I had another chance to ride in the back seat and give a close listen. Now it is clear that it is definitely in the rear suspension somewhere, I just have to figure out where. You might be on to something with the Sway (stabilizer) bar end links.

This website has some good diagrams of the rear suspension, but I provide it as an reference only, I do not in anyway condone purchasing from this site: http://www.newgmparts.com/parts/1999...R%20SUSPENSION

I think I may have come across the source of my rattle.

Follow the link to this diagram: http://parts.nalleygmc.com/images/pa...09GM07-044.JPG

Item 49 on the diagram seems to be the source of the rattle. If I put a screwdriver on the center part of this isolator while someone is kicking the tire I can minimize the rattle. The only problem I have is, what on earth is this thing called? I think these are the GM part numbers for this item.

15237959
15237959 INSULATOR. Rear Axle Control Arm


15237958
15237958 INSULATOR. Rear Axle Control Arm

I'm going to try and go to the junk yard tomorrow and see if I can take one off to figure out the mechanics of how it is mounted and to see how hard it is to remove the mounting bolts. If the one I take off looks in good shape, maybe I'll use it instead of trying to order a new one. I don't believe I'll be able to source this part from one of the local parts stores.

Today when I was about to go to the junkyard I was checking to see what size wrenches I would need to remove the isolator and I discovered that the bolt securing the isolator was loose. I tightened it, but I'm not sure how tight it should be. It is item 19 from the diagram posted in the last posting or attached. Does anyone have an idea what the torque spec on these bolts is???