I know there was another similar thread, but it didn't address my question. I just bought a 2000 Tacoma, SR5, TRD, 2.7, 5sp man, 4wd, 120K miles. I want to change all the fluids, including engine oil, tranny & xfer case oil, F & R diff oil. The guy on the phone told me that with that many miles I should just stick with regular oil. He also seemed to indicate that if the vehicle has not had synthetic in it in the past, I shouldn't start now.
What is the problem with mixing oil with synthetic? How do I tell whether the truck has had synthetic in it, and why shouldn't I go ahead and change to synthetic now if it hasn't had it before?