I have a 97 F350 4X4 7.3 with a rebuilt heavy duty Jasper automatic tranny, so it shifts a little harder then stock. The issue is at shift, but not all the time. There seems to be loud chirp coming from the front end (usually first to second, second to third, on harder accels). It also occurs at shut down but can't seem to nail down the location. I'm thinking it maybe a pulley or the serpentine? I never noticed it through the winter but noticed it a little at the end of last summer and now it's reappearing.