I have a factory 12bolt truck positraction carrier for sale. Its a 3-series unit, 18 disc solid steel clutches and 200lb (green) springs.
$300 plus shipping or $325 shipped anywhere in the lower 48.
I also have a like-new Richmond 3.73 ratio ring and pinion set. Its been installed (not by me) but never run that I can tell. Its their Excel series and is made for a 3-series carrier (Thicker ring.) Ring and pinion only. No bearings or crush sleeve.
$140 plus shipping or $160 shipped anywhere in the lower 48.
Both for $420 plus shipping or $465 shipped anywhere in the lower 48.