Rattle only presents with clutch out and gas peddle depressed in gears 4, 5, and 6 at around 1500 RPM - 2000 RPM. Rattle disappears after that. If the diff is in neutral the rattle can be reproduced in gears 4-6 (6 being the loudest) 1-3 can't hear anything. I took down the sifter boot and noticed the second boot (inner boot) was torn, so that will be replaced. I suspect that will only dampen the noise. Other forums have said heat shielding, it just doesn't sound like that. Its a fairly loud rattle bordering on grinding.
It stinks like some sort alignment issue with the clutch rebuild. There was no rattle / noise / grind before I had the clutch rebuilt. I had the entire clutch done because the TOB blew on my way home about a month ago. Drove home 1 mile and parked it. Had it flat bedded to the mech. Mech is very well regarded in the area as a jeep 4x4 place. Jeep sat for 1-2 weeks while I ordered all the parts.