Automatic Transmission Fluid is looking brownish on my 2004 Corolla. The car has 156,000 miles on it and drives just fine. I don't know when the fluid was last changed since I bought it used at 150,000. Should I change my transmission fluid? Would changing it cause any issues?
Check the FAQ.
The FAQ recommends to keep old fluid if uncertain. If I have problems after changing the fluid, does putting the old one back in help?
Maybe.
Thanks, I appreciate it.
These people with similar mileage (or more) had good results. So have I in the past.
My transmission guy would say "no problem".
And Scotty has said multiple times that Toyotas generally don't have problems with ATF changes, even at higher mileages.
https://carkiller.com/scottykilmer/qa/2005-chevy-colorado-shifting-issue/
https://carkiller.com/scottykilmer/qa/transmission-problem-with-my-2005-camry/
https://carkiller.com/scottykilmer/qa/matrix-transmission-issue/
If your transmission is in good shape, then I will tell you this for sure: it will fail a lot sooner if you don't maintain it.
If you don't know the service history for the ATF I won't touch it. Like Scotty says it can cause the transmission to slip, It's a long shot but try something like Carfax maybe they can find public records, not too familiar with it I might be wrong.
I'll just try to take it to someone who knows about transmissions and see what they say. Anyways, thanks for the tip.