Joe, First I apologize to everyone for not proof reading the title of my post. It says HIgh Desert Package severe leaking proplen. I obviously meant High Desert Package severe leaking problem.
I had a 2011 and a 2013 Avalanche. The 2011 was purchased from the dealer stock. I ordered the 2013 which was the Black Diamond Edition I loaded with just about every option available. I loved both of them and was extremely disappointed when Chevrolet discontinued them. I never had one drop of water leak into either Avalanche.
In mid 2016 when I saw the first pictures of the Silverado with the High Desert Package I was really excited. The package was originally supposed to be available at the start of the 2017 model year in September of 2016. However, it didn't finally become available until late January 2017. I ordered mine February 23, 2017 and took delivery April 20, 2017.
Right from the beginning I had problems. The top side storage boxes didn't close properly. One of the rear panel locking levers had the yellow trim cover missing. I only had it a couple of days, and after a rain storm I opened the tailgate to find a lot of water inside the box. The system they used for the tailgate to close against the rear most panel is ridiculous. It leaks after every rain or snow storm. The tailgate should close under the rear panel not up against it.
The dealer kept it overnight a year ago and performed all kinds of leakage tests while an engineer from Chevrolet was there to observe. I've been told several times that new panels are being designed, and the ones in my truck will be replaced at no cost to me when they are available. However, the service manager told me there would be a disclaimer that the High Desert System wasn't intended to be water tight. Nice to know after I had tied up $6995 for the Package based on my ownership of two Avalanche's.
Unfortunately the service manager, who was very familiar with the problem, passed away last week after a short battle with cancer. I have little or no hope Chevrolet will correct the problem. Especially after the length of time which has passed with no action on their part.
I've told the dealer several times that if I could afford it I would remove the High Desert parts from the box, install bed rail protectors, a bed liner, led lighting package, a tailgate protector, tailgate top protector, and a tonneau cover. I've had 5 other Silverado's, 2001, 2003, 2005, 2008, and 2015, with tonneau covers, and never had a leak with any of them. And it didn't cost me $6995 for the tonneau covers.
My Silverado is the High Country model with a 6.2L engine. I love everything about the truck except the High Desert Package leakage fiasco.