Rear axel making bump sound

[tyhuck]

I have began to nitice that the rear axel of my truck is making a bump noise when I get the truck shifting from side to side. I first began to notice it when I went offroad and got a little offcamber or hit bumpy parts of the trail. Now I think Im hearing it on the highway when I hit rough parts of the road.

 

When I first heard it I thought something was rolling around in the bed, but I looked and nothing was back there. So, at work one day I jacked the truck up and felt for play in the rear exel. I was able to move the rear wheels slightly in and out. Didnt seem like it was anything to be concerned with, but I feel like its getting louder, or maybe its just in my head.

 

I bought the truck almost a year ago, but it had a performance muffler, so I dont know if the sound was always there and Im just yearing it because I put a stock muffler back on, or if its a new development.

 

Is a slight play in the rear normal, or is something weraing out with almost 100K on the truck?

[gmtech4]

slight movement is normal,

 

if you rock the steering wheel (from center to 3oclock,for right side and center to 9oclock for left))back and forth vigerously making the front side of truck raise while going slow and hear the noise have the torsion bar crossmember mounts inspected

 

they are rubber mounted and by rocking the wheel you are unloading and loading the mount ,

 

i hope this helps

 

 

i say this cause the mounts are behind the cab and isolating where that noise comes from is difficult,,,

 

they can be checked using a pry bar moving the xmember at each side and watching the mounts,daylight can be see thu it at the top as well,

 

the 03 k2 HDs i work on fail on the right mount more than the left

[tyhuck]

I know its coming from the rear axel because I can replicate the sound by shaking the rear of my truck from side to side. The only thing I cant determine is if it is coming from the wheel end of the axel or from the differential housing.

[joshw1303]

I have the same issue, leaf spring noise. Mine is still under warranty and they just lube all contact points with some white lube compound.

[tyhuck]

Well, I didnt think it was coming from the springs. I guess it could be, but it sounds more like its in the axel tube itself. I actually have no certainty as to where its coming from other than somewhere on the rear axel. Was yours squeaking or making a clunk type sound. Mine sounds very similar to the slip yolk clunk I get when I take off from a stop. The only difference is that I can feel the slip yolk clunk and it only happens when the truck changes velocity or goes from forward to reverse. The bump Im describing only happens when the weight of the truck is shifted from side to side.

[gmtech4]

 

heres a pick off what i took today of the torsion bar mount ,

 

note the rubber separating at the top

[joshw1303]

Yup sounded the same. But when i took it into GM it was leaf spring rubbing noise. So they lubed it up.