Transmission fluid, which one?

There can be issues doing a full flush on a tranny with high mileage. How much is high mileage? Depends on how hard it's been driven and/or neglected. Generally, over 150K. This biggest issue is a flush can lead to a tranny slippage because the clutches in a high mileage ATF start relying on the accumulated clutch material floating in the ATF for friction. Take away that friction material and the tranny slips. Additionally, new ATF has detergents that could dislodge too much crud, potentially clogging orifices and the filter. The recommended procedure for high mileage ATF is to replace the filter and do several drain/refiils over a period of time.

 

I use the Toyota OEM fluid. ATF WS.

 

I also have a tow package. Do you know which line to remove from the front (pics if any). I did take a look at the transmission lines that and oil cooler lines, but from the oil cooler, I don't know which is the return line that goes to the transmission.

 

this has some pics.

https://www.tacomaworld.com/threads/diy-full-flush-for-automatic-transmission.68462/

 

WS Toyota.