Solenoid stuck on

I don’t know if you realize it, but there can be up to half-a-dozen solenoids controlling the flow of transmission fluid. That fluid flow and the path that is chosen by a combination of the valve body, sensors and solenoids also determines the gear choice. If the code that is generated by a diagnostic test reads: Valve 5 On then I think you have to start with the entire solenoid chain, which is what you did.

In your six-speed transmission there are three solenoid pairs used to ensure proper gear choice (one set for each set of gears). Now, it is quite possible that you missed the right solenoids when you swapped out the particular solenoid pack. There is at least one solenoid pack in the valve body — on the inside of the transmission — which could be the reason your technician is talking about opening up the tranny and repairing it. And, there is at least one set of solenoids on the outside of the valve body, which is the one you probably swapped out.

I think you are right that the problem is electronic or electric. Have your technician pull another diagnostic, while he has hi equipment out. It only takes a few minutes and it is the best way to find out what may be ailing your tranny. I think you will find that, at the end of the day, the problem is either with a stuck solenoid inside the valve body that needs replacement or it may be a combination of an intermittent solenoid switch (the thing the solenoid activates) working in combination with a sensor pack that may be failing, as well.

This is an interesting issue — please do let me know what happens.