I too have read many post of the GM hitch failures
When I bought my '06 Chevy, I towed my Rockwood 8315SS(6400lbs. est.) up I-55 with the factory GM hitch. I didn't like the feeling I was getting.
Anyone who has driven I-55 between Hammond & the Mississippi state line knows how bad this stretch is.
Two weeks later I installed the Putman XDR
rated at 16,000 pound weight distribution and tongue weights up to 1,600 pounds. We then traveled to the same campground up I-55. The difference in the ride was very noticeable. I was experiencing flex from the factory GM hitch.
If you'll be towing a heavy trailer with the factory hitch, replace it.