Has anyone done their own transmission drain/fill?

I know there's a few steps that complicate the process in order to do it right but I was hoping there was someone on here that has actually done it that could share their knowledge.

I just crossed 70k and I was hoping to do a drain/fill around 75k and then again every 50k.

 

Not on Tundra but I did on Tacoma. I tried several times with jumper to get in to check mode and never could. I just measured what I drained out and refilled with slightly more. I used a infared thermometer and took temp readings off the output line to the radiator. This worked for me. I pumped the replacement fluid in so you will need a pump. Do a search there is a write up on here.