I just had to replace the AC compressor (and dryer/orifice) on my 06 3500. Now when I get in and start the truck with the AC on, the damper doors pop and shudder (strange sound, hard to describe) about 6 times before they settle down. When the AC cycles off a damper noise occurs again. There was no noise before it had it fixed, and the repair work was only under the hood, not in the cab (right?). What might the reason this started just after the repair. Could it be a vacuum problem? any vac lines in the area of the compressor / dryer / orifice tube?