New to site with a 2003 Sierra 4.8, auto, 2wd. I have a noise(rattle) when starting out from stop or at low speed. Only hear it under medium to heavy load - NOT at idle or revving engine. Also hear what sounds like air pressure release when starting engine when cool and when shifting into second gear under medium to heavy load.. What can these noises be and are they related? Thanks for any help.
