KenMathisHD

The flat switch, are you talking about the pressure switch, the one that sits right there near the A&B shift solenoids?

I think what makes this preventative is once you have the solenoids out, you have access to the shift valves (at least that's what the dude in the video I looked at called them, I don't know if their actual name is different) in the little tunnel in the valvebody that the shift solenoids sit in and can clean them out. From what I'm reading, if your fluid is dirty, it can cause the solenoid to get stuck closed or open, so perhaps replacing them every fluid change or every other fluid change is a good idea to keep gunk from building up in the solenoid too and causing it to stick. I think it was more suggested as preventative maintenance in this case since the truck is at 109k miles on the original fluid and has some trans issues currently. It's possible the new solenoids help, but with the fluid being so old it's likely there's gunk in them already so replacing them keeps them from getting gunked up more and sticking later on. The ones you have super easy access to after taking the pan off, the A&B solenoids - are they both the same part number?They both look the same in the videos I've seen. And do they control 1-2 and 2-3 shifts, or 1-2 and 3-4 shifts? I'm not super clear on that. Want to make sure I'm ordering the right ones. Thanks! ~Ken

I'm ordering the parts to do a trans fluid and filter change in my 2000 sierra. While talking to a friend about it, he mentioned it would be a good idea to change the shift solenoids while I have the pan and filter off as preventative maintenance. What solenoids would I have easy access to with the pan and filter off, and are there any additional solenoids I should be changing that are not too difficult to get to? Is there anything else I should consider replacing while I have the pan and filter off? Truck is at 109k miles currently. Thanks! ~Ken