Kickdown adjustment

It won't kick down in low speeds shifts fine at like 55 mph just low speeds won't kick down.

Perhaps someone more familiar with the AODE will step in. I'm thinking that it may be either the Shift Solenoid and/or the electronic pressure control solenoid. I assume when you state that it shifts fine at 55 mph you mean at WOT it downshifts from OD back into 3rd but at lower speeds it won't downshift from 20 mph going to WOT back into 1st.
 
The factory tune sucks for the shift thresholds. Wes can tell you what the exact shift points are. I can't remember.

If it's acting really screwy, check your TPS since it's important in telling the EEC how far you've matted the pedal.

Good luck.