I’m going to second asemechanics advice, drop the pan, replace the filter and refill every 30,000 miles. Do that and you never need to flush or “fluid exchange”. Even though you don’t replace all the ATF this way, you replace enough to keep it fresh.
If you do a “fluid exchange” or flush without first dropping the pan and changing the filter and filling the pan with fresh fluid, then you will NOT replace 100% of the ATF either. You will only dilute it, its about as effective as just a drain and refill. But you only need to do the 100% ATf exchange if you have been severely negligent in servicing the transmission.
It really depends on your transmission and the fluid used. You’ll have to check your manual carefully. On my Pontiac, you drop the pan same as usual, but filling it again requires the car to be level and up in the air, with a side fill hole hard to get to. Plus no dip stick. Not good for a DIYer. So it was worth the $100 to have it done. Be absolutely certain they use the synthetic Dex VI if that’s what it calls for.
On my Acura, its a matter of a drain plug. No pan to drop, just pull the plug and use a new washer. While the book calls for it to be level also, it doesn’t really matter and can be done on ramps as long as the same amount is returned as was taken out. Also, I only use the $9 Acura fluid.
This is done every 30,000 miles regardless of what anyone else says or does.
Thanks gang. I’ll hop on this as soon as I take care of my check engine light. What is it about Indiana? Is it cursed? Our cars have been falling apart (at a faster rate, albiet) since we arrived here.