Trans cooler

Needs some suggestions, I got a 09 Tacoma prerunner, with no towing package. I’m in the process of installing the necessary to tow. This includes aux trans cooler. Is it best to fill the aux cooler up or should I run thru the gear and fill what’s needed from the plug at the transmission?

I figure I would probably have to fill up either way, but wouldn’t it Be less if I fill the radiator up when I install it. Thanks everyone for the input!

 

When was the last time the trans fluid was changed? If anywhere close to 60k miles on the current fluid id take the opprotunity to do a flush.

Id install the cooler and leave the return line to the trans disconnected. Then using the DIY posted here, pump all the old fluid through the new trans cooler, this will flush any contaminants out of the trans cooler and fill it at the same time.

 

I have not flush the fluid since I had it! The truck has over 120 k . I took it to a three shops and all stated that if the trans wasn’t having any issues at 120k that it wouldn’t be suggested to change it because it would probably cost some issues or it might not lol.

 

Ill post a link for you:
https://www.tacomaworld.com/threads/diy-full-flush-for-automatic-transmission.68462/

This is a different thread (drain & fill) but has some good info you should read. Including how to do the temp check procedure, which people get wrong all the time..
https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

Do the DIY full flush after installing the cooler to flush the new cooler too like stated. Your trans will thank you.

 

Just having recently installed and Aux Cooler with Fan. It was NOT possible to fill it prior to install because of the location of the inlet and exit ports.. thinking about your question, it would be a total mess of transfluid leaking everywhere if you tried to fill even if it was hooked up to the flow. Go with your first suggestion, fill through the pan. I would ensure on the return line, by unhooking and putting on a flex tube that the transfluid is returning and has pushed out all the air, then hook back up and fill as needed through the pan.