So I have been having some power issues with this truck for a long time and fighting a knock sensor and speed sensor code for 1 year and half now

I tried changing out the speedo cable and the exhaust got to hot and ended binding the cable up, my mechanic tried to tell me my cat was bad, BS I've done enough research on here to know that not only does the speed sensor/cable, when it is not functioning, can cause transmission lock up and you bet your ass after long driving my transmission also feels pretty damn hot, shitting is hard in first, like I mean, you feel these bucks but the hardest is in 1st

Now I'm dealing with a coolant leak, the previous owner changed the water outlet with an aisin one but not to sure if he made a good seal with RTV because this is where it is leaking and it's seeping onto the timing cover, so do I need to remove everything id have to remove anyway to do the knock sensor job, because at this point if I don't fix this code, this is going to start causing disaster effects all over the engine

Now funny thing is not once has this truck ever shown signals that' is overheating, the temp gauge reads actually below half when hot, the only time it ever got higher than half is when it didn't have the proper amount in the overflow tank

The other thing I have noticed is, the coolant was extremely dirty when I got it, almost orangish color, I thought it was oil but it actually may have been rust, I didn't know how to drain it at the time so I used a turkey baster to get as much of it out of the overflow and refilled with fresh coolant, probably is still somewhat dirty but looks definitely green where it's leaking