I recently completed this DIY ATF change using the information in this and other threads. In the interest of helping others, I thought I'd post some of my experiences and a few pictures and videos detailing the process.
First some of the other resources (besides this thread) that helped along the way:
This post helped me determine which transmission plugs I would be working with (pictures from a 4Runner, but the setup is the same):
T4R Transmission Fluid Servicing (sealed & non-sealed) - Toyota 4Runner Forum - Largest 4Runner Forum
This post helped me figure out how to jumper the OBD port to measure the ATF temperature (used for your final fluid level check):
THE OFFICIAL HOW TO: ATF Drain and Fill - Toyota Nation Forum : Toyota Car and Truck Forums
This post helped me determine which transmission line to detach from the radiator, and helped explain the whole process:
DIY: Full Automatic Transmission Flush - Toyota Nation Forum : Toyota Car and Truck Forums
Alright, on to the tools I used:
A container with fluid volume markings (or any old container that you can fill with 2 quarts of fluid to mark off the 2 quart level). This particular container was purchased at NAPA for the ridiculous price of $26, however I really liked the stability its base provided and the various measurement markings.
About 4 feet of 1/2"ID x 5/8"OD clear tubing, with a funnel that fits it. I purchased this at Home Depot for about $10. I marked the transmission end of the tube with several wraps of electrical tape at the 1 inch mark. You don't want the tubing to go into the transmission further than this, and the tape provides both a quick visual check and a mechanical stop for preventing this.
About 4 feet of 1/4"ID x 3/8"OD clear plastic tubing. Also purchased at Home Depot for about $10.
Pliers, zip-ties, and electrical tape. These will be used to secure the funnel and tubing.
Torque wrench for torquing the various bolts back to spec. I have been using this Husky wrench from Home Depot (~$70, 3/8" drive) for various FJ tasks and it has been very solid.
Various 3/8" sockets and socket wrench. For this project I used: 24mm, 14mm, 12mm, and a 5mm hex head. The sockets are Husky brand with exception of the 24mm, which I purchased individually at NAPA for about $5 or so (an employee had to pull it out of a complete set). A 15/16 inch socket also works very well, so depending on your truck you could try either a 24mm or the 15/16.
Oil drain pan (no picture). This is what I emptied my 2 quart measuring cup into. I recycled the oil (for free) at O'Reilly's Auto Parts.
Next up was locating and removing the transmission fill port. Using the official service manual and the threads mentioned above, I was able to locate and remove the fill plug. You will know you have the right bolt if it says "WS" on it.
Here is a picture of the fill port with the 1/2"ID tubing inserted. You are looking up at the transmission from the passenger side, with the rear of the vehicle towards the bottom of the picture.
Another angle showing the black electrical tape at the 1 inch mark.
This is how I routed the tubing towards the front of the vehicle (the engine bay is towards the brightly lit area).
Routing the tubing up through the engine bay, and attaching the funnel.
I secured the funnel to the hood with zip-ties. This proved to be super helpful in making sure everything stayed put.
Next was disconnecting the proper ATF return line from the radiator. I struggled with figuring out which line to disconnect, but using the above threads I was finally able to determine which line to unplug. For reference, I disconnected the return line from the passenger side of the car. The threads above (especially the bottom link I posted) have great pictures and descriptions of which hose to disconnect if my pictures aren't clear enough.
This is how I secured the 1/4"ID hose to the metal outlet fitting once I disconnected the hose attached to it. The 1/4"ID tubing was fairly difficult to attach, so I placed it over my needle nose pliers and pulled the handle apart to stretch out the tubing. The hose that I disconnected was folded up against the plastic radiator housing so that it wouldn't leak all over the ground. (Note: I don't think the zip-ties are necessary. There isn't much pressure in this line). In this picture I am lying on my back looking up into the engine bay, with the front of the vehicle to the bottom of the picture.
Another angle, you are looking at the driver's side tire.
And another angle, similar to that above.
Here is another view, showing the drain tubing connected and being routed to the driver side of the vehicle. The rear of the vehicle is to the back left.
The drain hose was routed over to the driver's side of the vehicle so I could watch the old ATF draining while I was in the truck.
Now on the driver's side, I taped the drain tubing into my measuring container so it wouldn't fall out. I also placed a line of black electrical tape at the 2 quart mark so I could easily tell when I had drained about 2 quarts. The oil drain pan was also close by for emptying the drained ATF from the measurement container.
At this point I was able to start the truck and allow the transmission's fluid pump to do all the hard work. This was the part of the process I was most apprehensive about as I thought the fluid was going to drain much faster than it did.
After draining 2 quarts, I would fill exactly 2 quarts of oil into the funnel. I would then empty the 2 quarts from my measuring container into the oil drain pan. I repeated this cycle until the fluid started coming out cherry red, which occurred after about 10 or 12 quarts of new fluid. On a few of the drain cycles I moved the transmission gears through their range a few times for good measure.
Once the fluid was cherry red, it was time to check the fluid level. I jumpered the OBD port as described in one of my links above and performed the ATF temperature check sequence. Once I got the correct sequence of lights to turn on, I left the engine to idle until the ATF light lit up indicating the transmission was at the proper temperature for level measurement. It took maybe 5 minutes for the light to come on.
I then left the vehicle running (with tires blocked and the e-brake engaged, with the truck in Park) and crawled under the truck. I removed the fluid check bolt (shown clearly in one of the above links) and let the ATF drain out until it was just a dribble, then re-torqued the plug to spec. I would say maybe 1/2 quart came out. I then re-torqued the fill plug as well.
Hopefully this helps anyone who is trying to decide if they can do this project. I thought it was about as easy as an oil change, it just took longer. I did use Amsoil for better or worse
Let me know if you have any questions or if you notice that I buggered something up.