whats up guys? this is my first thread so bear with me. I normally do my own repairs an diag, but there are a few issues that are kicking my ass. ok first of all i own a 2002 chevy 1500 z71 ext cab. 5.3liter. first issue is there is a double click noise after truck is put into either forward or reverse gears and the accelerater is pressed. I went a head an replaced front and rear drive shaft u-joints. no change. The noise is still there. Had my buddy get in the truck and re create the sound and i got under the truck and i it sounded like when there was a load applied the noise semed to come from the drive shaft area.??? kinda stumped and anyone seen a drive shaft fail?? ok here is the second issue. when truck goes into lock up on the highway the truck seems to surge. You can not feel it but def hear the engine and exhaust tone. The issue is only there once truck goes into lock up? any help would be greatly appreciated. Thanks guys.