1. Get the truck up on some ramps or jack stands. The key here is to get the truck high enough so you can sit under it comfortably.
2. If you have 4WD, remove the drive shaft that is in your way. It's just a few bolts and is out of there in minutes...easy. Just remember to index the shaft. It's always a good idea to put stuff back the way you took it off.
3. Get yourself a LONG ty-rap. Ty-Rap the trans linkage out of your way. You can go around the frame with the ty-rap and pulled the trans linkage cable close to the frame. If you dont do this, you'll find your arm will scrap against it every time you reach your arm up to the sensor.
4. Open the hood...especially if it light outside...makes seeing everything much easier. Grab a good flashlight too.
5. Now get your 1/4 drive stuff. Grab a small ratchet and an small extension. You'll need a 10mm and a 13 mm.
6. Now that you have the drive shaft out, sit under the truck on the drivers side, facing forward (as if you were driving). Now, the engine oil pan is gonna be to your right. Your head will be right next to it. Look up. The sensor is located behind a heat shield.
7. You'll need your ratchet and 10mm first. One bolt is pretty easy to see, the other you'll have to reach farther over to the passenger side to get at...but it's not that bad. There are two 10mm bolts. Use your extension. After that, you need to get the 13mm bolt out. It might be a little tougher to see, but with an extension not hard to remove. The 13mm bolt is on the drivers side of the heat sheild...just peak around with your flashlight and you'll find it.
8. Once you get those out, the heat shield is removed easily. Sensor is smack center of where the trans meets the engine. Right above the trans bell housing on top of a block that's connected to the engine.
9. Now, you don't need a SPECIAL tool to get this thing out. All you need is a deep well 27mm or a 1 1/16 socket and a 1/2 drive socket cap (for limited access areas) which you can buy at Sears for cheap. Some folks use a box end wrench cut in half.
10. Remove the connector to the sensor...just slightly raise the plastic catch and it slides right off. Clean the connector with contact cleaner. Remove sensor with socket, socket cap, and wrench (the wrench turns the socket cap). Easy...I'm mean relatively easy. Access is MUCH easier from the bottom.
11. Alternate way for removing connector: To get to the pigtail, go in the top, remove the 2 8mm bolts and pull the degas bottle out of the way. You can do it with the FICM in there, but its much easier if you pull it out and unplug the harness. Just be real careful not to bend the prongs. Getting an old pillow or seat cushion and laying on the engine will give you both hands free to do it.