It is not clear to me that Azadani was filling trans with ATF at the same time he was flushing the old fluid out...Isn't that how it is supposed to work? What am I missing?
I don't think you ever want the engine running/transmsission turning without a full pan of fluid...
No, I wasn't filling at the same time but I had a helper watching for bubbles. Here's how I did it step by step:
1. I drained the pan and filled it again.
2. I disconnected the return line from the heat exchanger and connected a piece of clear plastic tube to the heat exchanger outlet, running to a waste oil container.
3. Ran the motor in park until it had pumped out the torque converter and started to bubble. Dirty ATF came out.
4. Refilled pan (engine off) and repeated step 3. Clean ATF came out.
5. Changed the filter and cleaned the tray, refilled fully and topped off with motor running.
6. Ran motor for a while, shifting between all gears and used manual shift function as well.
7. Shut down and drained pan one more time. Unnecessary, ATF was clean.
8. Topped off again and am waited for car to cool for last running top off at room temp.
9. Started car cold in the morning with AC on and checked level. All good.
Probably a fair bit of overkill and fluid use, but if I got another car that was new to me I'd do it that way again the first time. Next time I may well drop steps 4 and 7 depending on the state of the fluid with the first drain, as I'll be using the same fluid and know the history of the trans servicing. I should point out that this trans had been done before, and the fluid was what I would've called "medium dirty". Definitely happy to have changed it, but it wasn't too bad.
At no time was there any noise or anything when the open hose bubbled, but I shut it down straight away. It was very quick to empty the trans, so I didn't get to move the shifter at all during steps 3 & 4. I worked the gears a lot in step 6. After all that I felt it was good that I rechecked the level cold (motor running) the next morning, as it did take a bit more.