Hey guys. Just got a 2012 Seirra SLT 1500 4x4 crew cab with the LC9 5.3 and 6L80 trans. Just over 7000 miles. It has two issues that i dont really care for. One is that sometimes when coming to a quick stop, the 2-1 down shift is rough. Enough that it actually surges me forward as it does the shift and im on the brakes. Is that normal? Is that part of the braking assist? THe other thing is i feel like it idles rough. I dont expect it to be perfectly butter smooth, but i feel like it runs alot rougher than it should. Is this something that lots of folks with the newer 5.3's are experiencing? Or should i take it to the dealer? It idles rough enough that when its in gear and im just idling forward (like a the drive through) its like i can feel each hit of the pistons. Hard to explain, but it doesnt just move smoothly forward. It moves roughly forward. Common? Dont worry? Worry? Dealer? Tune? Computer reset? I did buy it with 6000 miles on it already.

 

Another thing thats strange is ever time i start it and take off, i get two light clunks in the peddle area. one at about 8mph and another right at 10mph. Every time. Any thoughts?