Sika '05 Corolla LE39,750 milesI get the oil changed & fluids checked on a very regular basis at the dealership. Yet, I went to a tire store to have a nail removed, and they told me my transmission fluid was burnt & needed to be flushed. Now, I think they were probably trying to rip me off, considering they were going to charge me over $300 to do this, but it got me thinking, when should I have it flushed?The owner's manual doesn't say to do it at 30,000 miles, and I would have thought that the toyota dealership would have at least mentioned it if it were really burnt.Should I go back and have the transmission fluid changed out? Is it worth the extra money to have them do a 13-qt flush vs. a drain & 3 new qts? I haven't experienced any problems with shifting or anything.Thanks for your help!!