so i have a 97 auto awd, and I was wondering if i can put a 99+ trans in it and have the over drive/5th gear work?

do i need a 99+ ecu or will it just work?

and just for ***** and giggles what if i wanted to swap a 99-01 motor and trans what extra would I need? i could care less about the O/D button.[

i asked because for some reason a 99+ swap is cheaper than 97-98 replacement...jdm or usdm

thanks