I would also like to know this as well! I forgot to add some fresh fluid after changing the rad, .5 quarts?

 

Please follow Lexus procedure of monitoring temperature with software when checking and/or adding trans fluid. If you have over 75k miles, it's a perfect opportunity to do a drain and fill maintenance.

 

There really is no substitute for checking the tranny fluid level. When I replaced my radiator to buy some time this was the method I used. On the car side I capped both lines to prevent losing fluid. My oem new radiator came with caps on the transmission cooler. I filled the transmission cooler before installing it on the car with the caps in place. While on the ground I pulled the caps off and slide the lines on. Very little fluid was lost.

A few months later I changed the tranny filter and serviced it correctly.

 

That's some terrific forethought. From other threads, I understand that even 1/2 qt low can cause trans issues.