This is bad.

Im thinking; posts 25,30 and 36.I leave the seals in too after verifying clearance. That reverse/ok to forward not ok, though has me head-scratching.Wait this is a clutch type posi. Then maybe the last clutch is misaligned preventing spline engagement.Oh yeah,that could do it.The end of the axle would press on that errant plate and jam it up.