Hello scotty. I have a 2011 Silverado 1500 with the 5.3 and 6 speed transmission. Awhile back I noticed a scratching sound coming from the hump in the middle of the cab where the transmission sits. I noticed it on the interstate. I stopped at a gas station and thought something was under my front middle seat rubbing on the plastic and making that sound. I found some stuff under there and threw it away and I thought that fixed it. Well probably a month later I noticed it again on a two and half hour road trip one way on the way there and back. I did that same road trip a week earlier with my music off and didn’t notice it. After the first time I heard it it has since had a transmission fluid and filter change and a TCM update. It had been about three weeks later after the fluid change that I heard it the second time. The dealer said the fluid was in pretty good shape and there was nothing out of the ordinary when they changed it. I checked it yesterday and the fluid looks beautiful. I have only noticed the noise twice it may have done it another time and I couldent hear it because of the radio. I drove it on the interstate today with the radio off and didn’t hear it. The truck overall shifts good it does have it’s weird up shifts and down shifts but I have been told by MULTIPLE people that is just the nature of the 6 speed transmission. I am going to get a tune put on it that will fix that. Here is a link to the video and if you listen past the tire noise you can hear a scratching sound. What do you think is? Should I he worried about it?
those are pretty much garbage trannys, but do put it up on a lift and run it and pray that it's something like a worn u joint or bent driveshaft rubbing that can be seen and not internal tranny wear