I disagree, Almost all manufactures do have fluid intervals listed. If there is no information on fluid exchanges, I keep old school practices, 3k to 5k on conventional oil changes. 50k on almost all transmission fluid exchanges. 50k to 75k on newer vehicles cooling systems. almost all the newer cars and trucks the fluids can last longer, not to say they should be extended, I think the way to keep cars on the road is to keep fluids current. It will do nothing but keep the life of that vehicle. Yes if fluid looks dirty, exchange, and don’t forget about the needed filters required sometimes.
Ramon Elder (ELDERAUTO) Denver