Not necessarily Gus, I had one on my 95 GA bust the flex plate. It made a grinding noise for a little bit and that was that because the TC pulled back a tad into the trans and no longer made contact with the flexplate hub.
In his case of no D or R with high fluid level, a TCC valve only controls the lockup TC. As long as the engine is spinning the TC, and the pump shaft is connected, he should see a drop in oil level.
I think he really needs to go out and at least verify that the flexplate is turning the TC. That way we aren't still sitting here playing guessing games.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8