I know it's getting hotter but if my radio is on about an hour it says it's overheating and then shuts down.

When I get home I'll check to make sure the fan is moving but doesn't seem like a good thing.

It has been about 105 here so it's hot...

Duane...

I am curious what the outcome is, I have 2007 Silverado Classic Crew Cab, with the 4000NEX, and have not had any issues, We have close to same vehicles and probably close to the same weather. 

Might not have it ventilated well enough.  But then it could be a DOA fan.  That is a bummer, if it is the fan at least you can get it replaced.  But if it's ventilation, that is trickier

So driving home it died again but I was able to pull it out. The fan works and I moved the cables and such around and put it back together. I have an hour drive here in a bit so I'll crank the tunes and see what happens.

On a positive note it didn't really have a lot of time to cool down and it was on and running, including the fan, while I was moving things around. So REALLY hoping it was a ventilation problem and I have it worked out. Will know later tonight.

Okay I'm keeping my fingers crossed but it seems like it was an airflow problem. I moved the cables and it seems like it's working. At least it's hasn't overheated within the time it had before. I'll try to let it run longer today.

It's nice of them to put a thermal sensor in there and shut it down instead of it just burning up.....

With that said with these "modern" fan-enabled units I pay close attention to how things mount to make sure the fan and finned areas (heat sinks) are unobstructed by cables and such when the dash is put back together.  Hope you found the problem.

Just to follow up that was the problem. Ran it for hours today with no issue and haven't had any problems since.