In my car in first or second gear I can idle at low speed and hit about 1/2 throttle, the tach will flash to about 1700 and then the car pulls. If I'm higher up in the rpm's in 2nd (I can hold it because I have a lentech), I can hit it and it will jump revs just a bit not alot but maybe 200-300 before it will pull. In 3rd if I let off and get back on it, it won't jump revs at all, it's directly locked. OD is the same way. It's better for gas mileage this way, and you will pull higher MPH in the 1/4 mile with a lockup.
The factory AOD has a split path input shaft (hollow outer and thin solid inner shafts) When you shift to 3rd gear they lock and become "one". If you switch to a non-lockup convertor you must get a 1 piece input shaft.
The stock input shaft is a weak link, my friend broke one in his SC w/ only a 5% OD pulley, exhaust, and a Coy Stage 1 Cam and lentech valve body. Shifting from 2-3 it went bang and then CLUNK. Snapped the input shaft.
Notice how your car doesn't feel as strong down low in 3rd as it does in 2nd. Even around 2600 where the torque peak of this motor is (assuming mostly stock). I can feel the convertor lock on mine. It makes the 2-3 shift really harsh and it will get rubber. I guess when I get a non lockup convertor the 2-3 shift softens.