What is the difference between a L4 and S4 transmission on a 2003 outback 4 cyl 2.5L, auto? Should it be mantained any different? Thank you!
Follow the transmission maintenance recommendations in the owner’s manual.
If you don’t have an owner’s manual, get one.
http://www.Books4Cars.com might be a good source for an inexpensive used owner’s manual.
Many mechanics recommend replacing the transmission fluid every 30K miles even if the owner’s manual says you can go longer.
It’s not a bad idea.