Whats this noise?

[ChevMech]

I've done some searching and I can't find anything to match what I'm experiencing. If there is an existing thread, please direct me to it.

 

This is my problem. When I drive my 03 Z71 over an uneven road, I hear a knocking sound and feel a clunk under the floorboard. Also, when I put it in auto 4wd, or 4 hi, there is a groaning sound with the knocking.

 

My first thought was one of my half-shafts are going on. I jacked up the front end on both sides and both sides were smooth. The driver's side, however, felt like there was a knocking within the differential.

 

I also checked the front drive shaft, and when you turn it, there's a knocking feeling coming from the transfer case end.

 

With all of this being said, does anyone have any idea what I'm up against?

[gmtech4]

check torsion bar xmember mounts

 

get under truck ,find the mounts at each frame rail and put a flashlight on the other side and look thru the mount ,,,if ya can see the light thru it ,,,the rubber has separated ,,,its very easy to see it ,,,just get under the truck ,,,

 

the suspension unloading and loading creates a knocking ,,,,

[ChevMech]

I finally crawled under my truck to look to see if the noise was, in fact, those bushings. They look good from what I can tell. I will investigate more when it isn't so darn windy lol. Anyway, I noticed the bushings are held in with rivets. How difficult is to remove the mounts and rivets and replace them?

[gmtech4]

I use a cutoff disk and put a cross on the rivet head (carefull not to touch frame ),then use an air chisel and bark off the 4 sections of rivet head ,then punch the rest of it out.

There is a special tool to remove the torsion bar keys so to prevent personnel injury , have mechanical common sense and get the tool

 

Use grade 8 bolts if ya do it your self ,,torsion bars can be a bear to push forward out of key/control arm ,use lots of lube and air chisel with u-joint bit

[Beer Belly]

Had this issue with my '06...dealer said "they ripped out"

[bmp5484]

Had a similar noise in my 03 and ended up being a bad idler arm.

[ChevMech]

Last week I finally got it to a mechanic. It turned out the torsion bar cross member bushing were fine. The problem was the front end in its entirety. What we found were bad tie rod ends, idler arm, pitman arm, and a worn out wheel bearing on the passenger's side. Since it would have cost upwards of $2000 and the truck had 203,000 on the clock, I traded it for something newer before the fit hit the shan. I hated to see her go, but my 2009 Silverado 2500 HD is something to see. Thanks for all the help on trying to figure this out!!!

[SILVERADOSC540]

Congrats on the new ride, post some pics.