Transmission started to act up, anything should be changed while the oil pan is off ?

[aureliusmax]

Hi.
My Transmission Gear Indicator Switch I know is failing due to intermittently getting stuck in failsafe mode at cold starts. But once I moved the shift level back and forth and power cycled the car, normal shift mode would come back.
This part is already ordered I'm just waiting for shipping.

On Saturday I was doing some spirited driving in Manual mode and started to get 'slam' shifts, from 1-2 and then 2-1. Regular drive mode doesn't work too well either. When the transmission shifts in drive the engine RPM goes up, there's no engagement to the clutches and then the next gear finally engages with a slam. As well going from park to drive, and then there is another slam intermittently.

I also have noticed since when I got the vehicle, sometimes it takes a good 3 seconds to downshift from a pedal kickdown.

However I do know the clutches and torque converter are good because wide open throttle response in sport mode is to me appearing as it was before I noticed these issues.

My game plan is to drain the fluid (no service history), change the filter. Add new AMS oil synthetic transmission fluid and some seafoam transtune, which I have used before on chrysler and GM transmissions with success for when things needed a good cleaning.

I do realize on most transmissions the solenoids like to go out around the 200,000KM mark, so maybe replacing them is a good idea but I haven't done it before.

Anyone have an idea if the valve body and solenoids can be changed with removal of the oil pan ? Is also changing the Wiring Harness With Temperature Sensor a good preventative maintenance idea ? Any other 'while you're in there' maintenance tips ?