So..... i'm 50/50 here on if i should flush my auto trans once more or not. 3 weeks ago I got water in it and was looking at a strawberry milkshake situation. I dropped the pan, cleaned the magnets and screen, and then disconnected the return line from the radiator and methodically removed the milkshake 3 quarts at a time, each time adding 3 quarts through the dipstick. I put 8 quarts of gas station atf, then 16 quarts of synthetic. I originally used Valvoline synthetic, but at the end of the process I was low on the dipstick and I added a few quarts of Mobil 1 synthetic. I had a few transmission issues, and i brought it to the dealership, and they fixed it by adding a little more ATF, the quantity and exact type of ATF I am unsure of.

Now, in 2 days, i'll be pulling a 6x12 uhaul trailer 460 miles. I could drop the pan again, put in a new NAPA filter + gasket, and flush out the synthetic in there for 11 quarts of AMSOIL. That will run me about $200. At the moment, the transmission runs great, but it bothers me that there are 3 different brands of ATF in there. I did a lot of research and it turns out the 4runners had defective radiators that caused this strawberry milkshake water contamination issue a lot, and those who saved them ran like 60 quarts through. Overkill? Maybe... i don't know. Another benefit would be that i could check the magnets to see what ended up there after only 2.5k miles. If there is a lot of metal after such a short period then I know I can start shopping around for an R150f....

So.... if it aint broke don't fix it.... or should i bite the bullet and go for piece of mind? My biggest fear is that, even though i've done the flush before and im sure i could do it in 3-4 hours but if for somereason something goes wrong... im kinda ˟˟˟˟ed because the Uhaul is all reserved and i need to move into my new apartment.

Thoughts?

 

If you are gonna flush it I would take it to a shop and have them hook it up to a machine to do it properly. They will connect it to the outlet and inlet cooler pipes and the old fluid comes out while new fluid goes in.

I would not mess with it manually, I would consider having that treatment done. Then draining the system yourself and refilling it again with quality fluid while changing the filter ect.

The transmissions don't generally last long after a situation like this so you really need to decide if you want to spend the money trying to save this one or looking for a replacement.