[jhv48]

As a follow up. After about 1500 miles the grinding returned. Pulled the trams and examined the throwout bearing. The center section that rides on the trans bearing retainer was scored. After removal, we found a small burr on the retainer shaft where the throwout bearing rode. We surmise that the burr was scoring the t/o bearing causing it to drag just enough for the clutch to fail to completely disengage the trans.
Polished the retainer and no problems for the last 4000 miles.