3 spd auto vs 4 spd auto ID ?

[airboatphil]

Test drove a nice 2002 CE model yesterday......probably going to buy it..........I forgot to take note at the shift pattern to see if was a 3 or 4 spd......can someone explain the difference or post the tranaxle codes so I will have that info handy ?
Now, the real question.....with the hood up and engine idleing.......I hear a high pitched whistle sound (simular to a vac. leak?)coming from the area under the cover that fits over the top of engine....the sound will quit when you sweep the throttle...but return when engine gets back to idle ?.The engine does run well....I doubt it's vac leak...maybe a canister purge that is whisteling ?
Thanks in advance,
Phillip