4 wheel Driveshaft Noise

[Crystalblueseas]

I have a 2006 Police Package Tahoe. I have been restoring it for the last 5 years. It is four wheel drive with all the traction control enhancements. I suddenly had some noise coming from underneath my truck when I was getting ready to drive out on the beach. It was a spinning like noise. When I took it to my mechanic for advice we put the truck up on a lift. It seems like the noise was the 4 wheel driveshaft spinning. We put the truck into gear not 4 wheel drive and this happened. Anyone have this problem? What is the fix? There is no engine light on and the 4 wheel drive works fine. Would love some good advice. Thanks.

 

[Bill 1960]

Firstly, does this have the 4x4 auto function?

Secondly, not to be a jerk, but if your mechanic had it in front of him, on the lift, and you’re asking US what’s wrong then you need to find a new mechanic.

 

[Doubeleive]

my first guess would be u-joints

 

[Joseph Garcia]

I'm assuming that your mechanic checked the entire drive shaft assemblies and all other rotating components, while the truck was up on the lift. What potential items did he rule out, during his review?

 

[Crystalblueseas]

I'm assuming that your mechanic checked the entire drive shaft assemblies and all other rotating components, while the truck was up on the lift. What potential items did he rule out, during his review?

It looked like he ruled out the transmission, the transfer case shifts correctly. CV joints brand new. I will look at the universals on the 4 wheel drive shaft. Any suggestions?

 

[Rocket Man]

There’s a front drive shaft and a rear drive shaft, not a single 4 wheel drive shaft. So you’re talking about the front one I assume?

 

[Crystalblueseas]

There’s a front drive shaft and a rear drive shaft, not a single 4 wheel drive shaft. So you’re talking about the front one I assume?

The one going to the transfer case.

 

[Rocket Man]

The one going to the transfer case.

They both do. The transfer case is bolted directly to the back of the transmission, then one driveshaft goes out the back of it and one goes out the front of it, slightly off to the side.