I have a '99 with 115k miles on it. The 100kl service was done 6k miles ago. It recently developed a noise that is noticable between 1200 and 1800 rpm while excelerating. It doesnt happen everytime. It sounds similar to a playing card being ticked by a low rpm fan kind of. I can't pin point the noise exactly but it sounds like it could be from behind the radio area or even around the transfer case lever. It isn't very loud but it's noticable. No other symptoms are present. Any ideas on where to start looking? The AC controls don't seem to matter. You can have it on, off, auto, feet only, outside, recirculate, it doesn't matter. I've moved the transfer case into H, N, L and back to H with no luck either. Help please!