This shows the basic steps in replacement of solenoid A on a 2007 Toyota Tundra Transmission with 5.7, 4wd, and tow pk. My truck started shifting odd once. Turned it off and on and everything was ok. Months later, it would hold onto 1st gear longer than normal, and I started getting a check engine light and several other dash lights. After it sat for a week, it worked ok on a short drive. I decided to change the solenoid anyway. This is the process. Perform at your our risk, I'm not a certified mechanic.