After reading this thread last fall I decided the original GM hitch had to go:
Finally got around to installing a Curt Class V today. The original hitch was rated 6,000/600 without WD and 10,000/1,000 with. The Curt is rated 15,000/1,500 without WD and 16,000/1,600 with - well over the capacity of the 1500
Silverado. The Curt weighed in nearly twice as heavy as the original round tube. The difference in construction is easily apparent.
Curt Trailer Hitch Receiver - Custom Fit - Class V - 2" Curt Trailer Hitch 15522
Just wanted to thank Robert Cross and others who recommended this change - your insight is much appreciated.