Strange Noise From 03 Z71

[polar21]

The truck has around 130K on it. I was driving down the interstate and began hearing a noise similar to a plastic bag being stuck under the truck/a bearing going out. The noise does not occur if the truck is just idling, but the noise gets louder the faster the truck is going.

 

I did some research online and a quick test to see if the wheel bearing was going bad is to push on the top of the tire and if there is play or a noise then the bearing is bad. I tested the drivers side and it did not make a noise (I had the wheel bearing replaced on this side 12K miles ago). I proceeded to test the passengers side front and when I pushed on the top of the tire it made a clicking sound. So....I tore that side apart and put on a new hub assembly. Took the truck for a test drive and the noise is still there. I pushed on the tire (passenger side) and the clicking is still there. Could this be a bad U-Joint or CV joint going bad?

 

Thanks for the help.

[00Silverado4x4]

Get your passenger side up and have someone push/pull on the tire while you look around for whatever else might be loose/worn. That's the easiest idea I have off hand.

[polar21]

Update on this:

 

Come to find out the shock bushing on top of the shock had broke off and when I pushed on the tire the nut/washer on top of the shock was hitting the frame, causing the clicking sound. I have skyjacker shocks on the truck.

 

So the noise is still there and looks like I am going to have to break down and take it to the shop. Will update and see what they have to say.

[polar21]

Another update. Took the truck into the shop and the mechanic said it sounded like the transfer case. After reading about problems around the NP246 TC, it sounded eerily similar to what other people were saying on the forums.

 

So, I went and bought a couple of quarts of AutoTrak II and, after draining out a whopping 1/4 cup of oil, managed to put about 1 3/4 qts in there. Drove it around yesterday and the noise was gone...hallelujah.

 

I crawled under the truck today and the freaking oil is all over the place under the truck. So...I have a bad seal/leak somewhere under there. I plan on jacking up the back end and putting it in drive and see where the leak is coming from. I havent had any problems with this truck until this thing hit 100k miles. Its been nothing but crap since then....

[Gregs]

sounds like it might be the infamous pump rub

[polar21]

Could be that, but from what I have seen the pump rub creates a small hole. A small hole would not have slung the oil all over the bottom of the truck. I just went and purchased some jack stands and am going to refill the TC and put the rear wheels in the air to see if I can see where the fluid is coming from. This truck is pissing me off...

[polar21]

So I was a victim of the pump rub. There was a pin sized hole in the TC and caused the oil to go everywhere. I mixed up some JB Weld and put it on there and it is holding strong. Hopefully I can get 50K more miles out of TC...