I was planning to have my transmission fluid changed, (2003 HSE, 160k miles) but the indy shop kinda talked me out of it. They were saying, shocking the system with new fluid may cause slippage down the road, and I would be better off leaving it alone. Everything runs perfect right now, I want to do preventative maintenance, but maybe it's better to save the cost a fluid change ($500) for a transmission rebuild down the road since it may be due in the next 40k miles? I bought the car with 140k, no record of transmission fluid change, I'm planning to keep the car for a while. We use it mostly for towing, never had any overheating or transmission issues. Has anyone experienced a failure resulting from a fluid change?