Poser
WKR
My 2007 4runner is sitting at 259,400 miles. I bought it at 247,000 miles 1.5 years ago. I have no idea when it was last changed, if at all. A friend from church is a manager of a local trusted repair shop and said they won't flush the fluid for me because it's too risky with the mileage. In your opinion, is it still safe to drain and fill the transmission fluid?
IMHO, yes, a drain and fill *should* most likley be fine. I have been in your exact situation before with being at 250k and an unknown history of transmission fluid changes and have done drain and fills.
That being said, there is a school of thought that, at the mileage with an unknown history, you might consider just leaving it alone entirely and driving it until the transmission fails, but that ultimately depends on what your goal is for the longevity of the vehicle.
Have you tried pulling the CarFax history? If the transmission has been serviced at a shop that may be noted in the vehicle history. Of course, not all shops submit maintenance info to Carfax, some people DIY and "transmission service" is usually the only detail you will get if you do get any info at all. If "transmission service" was performed at a dealership, it was probably a flush. You might also take the vehicle to the shop of the mechanic you were talking to and have the maintenance condition further evaluated -how dirty if the diff/transfer case fluid, for example? If other fluids appear to have been maintained, that may lead to more confidence in making a decision.
If you want to take a deep dive, check out the The Car Nut Guy youtube channel. Its a Toyota mechanic and he has some videos on this exact subject.
