Mine is an 04 4.8is with 75,000k on it. There is a real shift lag between 1st and 2nd gear, when it finally shifts, CLUNK!! I try to baby it and modulate the throttle for that shift but it is driving me nuts. Had the dealer diagnose and they left me a voicemail just now decribing a transfer case error code. Can that really be it? I am on my way to the shop now to dig in... stand by.