One problem related to noises during shifting has been reported for the 2003 Chevrolet C/k Pickups. The most recently reported issues are listed below.
Drive train: clunk/clank during upshift under light/easy acceleration. Also during downshift such as when slowing for stop lite. Also dduring slowing for turn or upon quick acceleration. Vehicle has 4193 miles. Problem has been with vehicle since new! oct '03. Vehicle also has dead spot in accel when this problem occurs. Note: when shifting trans (at) from park to drive or to reverse or any combination there is a very noticeable delay in the trans shifting. This could be related to overall problem. The clunk/clank noise is very noticeable. Very audible,not only that, you can also feel it. N my opinion this could cause a loss of control if vehicle fails to shift when needed. Apple Chevrolet in red lion,PA said noise is normal. Bull!.