I have a 2005 Toyota Matrix with about 127,000 miles on it. I bought it when it had around 113,000 miles on it. I recently found a pretty good at home mechanic who I've had work on my car with now issue. He checked my transmission fluid and said it had a burnt smell to it. He suggested I changed the fluid, filter and gasket while I'm at it. I don't know the history of the care well enough to know if the transmission fluid has been changed by the two previous owners. I watch Scotty's videos and he says if its been too long to not change the fluid or it could cause slippage. Should I forgo changing the fluid and just have him do the gasket and filter or risk it and have him change the fluid as well. I want to keep this car for a while so if changing the fluid wont hurt the transmission and insures longevity I'm all for it. But if it prematurely ruins the transmission that would be unfortunate. (P.S. as of right now the transmission runs fine now with now issues, it just has a leak which is why it needs a new gasket.)

Thanks