What in the world is a small stream? If it's empty, you add a quart and run the process again.
Oh and doing this all is within inches of the hot exhaust.
So stupid.
I'm honestly not impressed with Toyota transmission, I helped a cousin put a cooler on his Sequoia because it pretty much ran 200F empty. My 3/4 ton has occasionally hit that temp, but it was pulling a 7k load up a mountain pass in triple digit heat.
I would be surprised if many sequoias last very long as tow vehicles. It would only cost $150 to install the tundra transmission cooler from the factory (that's all we did), and the temps became reasonable again.