I have a 93 Ford F350 4x4 with a Cummins 5.9 connected to a zf-5. I'm experiencing what sounds like chirping when the truck slows down such as when going down a hill with the cruise on. I also notice the noise when slowing in second, third, and 5th gear. When I have the window open, the noise is more like dry bearing squeal than a chirp. This noise seems to come from the transmission rather than from the transfer case or rear end. The fluid in the transmission is up to the fill opening and clean. Any Ideas?