I have a 1997 Tahoe w/68k miles and when I take off there is a clanking noise (sounds similar to a cowbell). The noise quits when I am at a constant speed and also when I put it in neutral. I've looked underneath and can't find anything that is loose. I'm thinking it is something having to do w/the driveshaft and am going to replace the u-joint for starters.

Any recommendations or help would be much appreciated.

 

Chevrolet just released a bulletin saying to replace drive shaft yoke with a new nickel plated one now offered. A friend just did it and he said the noise is now gone. I think he said the yoke was about $100

 

The new Rear Drive Shaft Nickel-Plated Slip Yoke STB is to address a problem with a clunking noise that is heard and felt when shifting into and out of gear and also during periods when the throttle is pressed hard and then abruptly released.
There is small chance that the new slip yoke may fix your noise but I doubt it.

I would first have the dealer make sure that you have the latest calibration in your vehicles VCM, there is a noise caused by the lock-up torque converter that sounds like what you describe that a new software calibration fix’s.
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Also, if your vehicle has metal Nerf Bars installed without rubber isolators they can transmit weird noises into the cab.

And lastly I would disconnect the exhaust flange and install new updated exhaust pipe seals on both manifolds, P/N 15093974.

 

Dave,

I can second the noise of aftermarket nerf bars. I had it on a new pickup, bought the cheap ones and couldnt figure out the noise! I finally took it to the shop and it was the darn CHEAP brand bars.

The next time I purchaed a good set and didnt have the problem. Funny how tryin to save a dime always causes issues!