At 60k I did the first ever transfer case drain/fill on the 04 F-150 in my sig. Never had an issue with any audible noise from the trans case and has always gone in/out 4WD no problem. When I did the 60k drain the fluid looked pretty worn and had the look of metal shavings but no metal I could see with the eye. Maybe just break in stuff. (front and rear diff's looked great IIRC). Changed it with MaxLife and 30k later just did it again. Same situation, the fluid looked like it had some metal content, no pieces or chunks and it still sounds quiet and get in/out 4WD no problems. Thoughts? I should have grabbed a sample but I'm so not use to doing that I didn't think of it. Normal? Time for a magnetic drain bolt? What could be going on in there?