tranny problems. HELP!!!!!!!!

tranny is shifting hard and late from 1st to 2nd gear.all other gears shift fine.just put new engine in car and went for a ride and thats what happened.
about 5 quarts of AT fluid spilled outof tranny when i changed an axlewhile motor was out.tranny was fine before that. O\D lite flashes 16 times at startup.check engine lite is on.2 o2 sensors are bad. someone told that could be problem or the tp sensor. what did i do wrong?

...what did i do wrong?

- nothin. its called L-I-F-E. when u do smtg, smtg happens. no do nothin, nothin happens...

I'd check these [follow links below - dont ask: clic clic]:
- TCU codes, connector pins from manual
- fluid level, get airbubbles out p.24
- charge voltage, also at TCU pins
- TPS linear resistance p.6, TPS linear voltage at TCU pins
- drop down resistor & pwr/comfo switch

found the problem.the cars idle would go up when put in gear so i tapped the tps and the idle went down to normal. i think it was loose.tightened it up and she shifts perfect.