I have this ticking noise in my 05 Avalanche 2500, It seems to only appear while under load like heavy-ish acceleration and its so quiet that I can only hear it when driving past a wall or another car, Its been making this noise since I bought it 2 years ago. I've heard some people says it a normal noise but It hasn't caused any issues so far. I do use Shell Rotella 5W30, idk what oil was in the vehicle when I bought it