Signs that a u-joint is going?

[Hookmaster]

I have a 2004 Z-71 Silverado Crew Cab. About a week ago I noticed a soft clunking noise when starting or coming to a stop, probably less than 5 mph. This is coming from the front end and sounds like the driver side. It doesn't do this at any other times. Two times now I have heard a hum/whine, once at 60 mph, the other at 45 mph that lasted about 15 seconds. I pulled the left-front wheel and the brakes and cv boots look OK. Does the front drive shaft turn on these trucks when it's not in 4-wheel drive? Any other thoughts on what it could be?

[jwhjr]

Wheel bearing? Is there any play on the wheel from top to bottom?

[Jeremy airjer W]

When you hear the hum/whine again turn the wheel to the right and left and see if the pitch changes or goes away. If it does than I would go along with the wheel bearing as well.

[Hookmaster]

No play in the wheel.

[Shack]

They do not have to be loose to be bad/going out.

Jer's advice is a great way to determine a wheel bearing failure.

If it is a wheel bearing, with the front end raised and using a stethoscope on the hub/knuckle, you can spin the wheels and find out which one is causing the issue. You will hear a high amount of noise from the bad one.

[morefishplease]

I have a 2004 GMC Z71, and have recently had the front right wheel hub assembly replaced and had U-joints done a month ago and I agree it sounds like the wheel bearing, what you have described with the whine/hum is what I experienced with a loose wheel bearing. That clunking noise could possibly be the slip yoke which I had clunk when stopping and taking off under 5 mph. When my U-joints went bad that was a loud skreech as the drive shaft was coming to a stop, usually the needle bearings shot making that noise. But, as I am not a mechanic, these are a few things that I have had go wrong with my truck that might help ya out.

[Hookmaster]

I took it in to the dealer. They traced the noise as coming from the transfer case. Waiting for a tech to finish a job before they can open mine up. I hope it's something simple.

[Snowking]

hook- what did the dealer find. thinking i have the same thing going.

[jwhjr]

I was wondering as well. Let us know how it turned out.

[Hookmaster]

When troubleshooting the transfer case, they took off the front drive shaft and turn the backwheels in gear. No noise in the transfer case. They then focused on the front differential which is from where the noise was coming. It was starting to bind up. They replaced bearings, seals, a spacer, a connector... Total parts $470, total labor $1176. I asked the service advisor if this happens regularly. He kind of dodged the question by saying he was driving down the highway and his front diff bound up and he had to replace the front diff and the transfer case. I almost took this up to Fergus Falls but didn't want to chance it so I may have dodged a bigger bullet. He also said if the gears needed to be replaced it would have been another $700.

I don't think this failure should happen. The reason I buy Chevy's is for the engine and drive train longevity I had on the previous 3 vehicles all over 120,000 miles.

I think I will have a bran muffin so I don't bind up.

[shorefisher]

Is the slip-yoke a big deal to fix. I have a small clunk when stopping and taking off slow and thought it was a u-joint going. But as talked about in this post a slip-yoke could be it.

[morefishplease]

To be honest with you I have no idea because I had mine done when the truck was under warranty but I know that I had only 16k on it when it needed to be replaced.