It sure sounds like the tranny thinks the engine is at WOT.
I'd try the adjustment again, maybe with a helper.
When my 86 needed adjusting, the mech had me hold it at WOT while he adjusted it.
96 T/A, Black/Graphite Leather, T-Tops, 6 speed, 10 speaker Delco/Bose "Monsoon"
Original owner, 188k miles and counting.
Total engine rebuild at 187,020 miles.
AIR delete. Bored .030 over.
Comp cams Xtreme Energy LT1 266HR-14 street cam and springs..
lift I .500 E .510 duration I 266 E 276