is my transmission on my 2001 ford explorer xls going out?

i bought a 2001 ford explorer xls a few months ago and only started driving it
a month ago. its not used often just random work trips. it  started to randomly
feel like the transission was slightly slipping when i used cruse control but
would stop after  a few seconds and it was very slight and it didnt happen
often. today it seemed to do the same thing for at least 5 miles then the
check engine light came on and stayed on.all fluids are full, no over heating
and the slippage wasn't constant. is my transmission going out or is it my
engine. i just hit 180,000 miles after buying it with 176,000. i had a 95
explorer before and that blew a engine after 125,000 miles. that was 10
years ago.