Thanks guys for the help, it turns out to be a 6L90 by the measurement of the main body, picked it up for $25 on a pallet from a closing machine shop sale.
It looks like it was pulled from a salvage vehicle as it has the transfer case and half of the front shaft attached, likely going to try as is if I can figure out how to attach it to a 6.2L diesel, the 0.667 final ratio will be better than the 0.75 of the 4L80E transmission being used in the late HMMWV trucks and should be more efficient than the earlier design (important with only 160HP)
Should make for an interesting swap...
It would have been better if it was a 6L80 though but you gotta play the cards you are dealt yes?