scannylada

On page 2 there was this post with same issues "engine-noise-heard-in-cabin-from-footwell-exhaust-leak-normal"

I have a 2017 sierra cc 6.2L gm borla exhaust. At about 400 miles I started to have the driving over rumble strips feeling at the same time as described above when you get your ticking sound. By the time I hit 3400 mi. I couldn't take it. Was almost embarrassing. Took it to dealer and they followed tech bulletin and flushed transmission 3 times. Got the truck back and the rumble strip shake is gone but now I have the tick at the exact same point that the rumble would happen. I thought the same things. Tried 93 gas in case dealer put in 87 since they put 250 mi on truck trying to simulate and confirm problem was fixed. Thought it might be exhaust leak but no signs of one. Have thought at times it might sound like a fluid rushing sound (something with the trans). Have thought about it being the flapper. Was going to try and prop it full open (waiting for weather to warm up a little). The fuel pump and or injectors could makes sense too