I have a 2011 LR4 with 212,000 miles. ZF6HP26 transmission.Manual shifter, not round pop up one. When tranny is cold it easily shifts to Park and Drive. When tranny is hot, more likely to throw tranny fault when placed in to park followed by "not in park" and won't turn off. Once this happens, there is a chain reaction with faults for brakes, flashing E brake, beeping, no HDC, all of that.

Factory scan shows p0915 and p0850 which have to to do gear selector and park/ neutral circuit. Tranny works fine when there are no codes. This tranny has not been serviced so the first try at any remedy was changing 4 quarts of oil. NO change. Cleaned all connections under shifter. No change. Swapped circuit board under shifter. No Change.

On the black plastic TCM, on the valve body, is a small portion of light brown plastic. This is the gear range sensor or gear selector. Looks like it slides back and forth with a circuit board on one side helping the TCM and other modules figure out what gears its in. Picture attached.

There are some services that offer repair services online and that's where I'm heading to solve the issue.
Questions for the Tranny Experts.
1) Can the range sensor every get so dirty, that just a simple removal and cleaning solve the electrical glitch? Wondering if the sliding plastic piece has a magnet in it and can attract junk.
2) Anyone every send their unit out for repair? About $350 to $500 is the quote right now including bench testing looking at all aspects on TCM.
3) Should I think about reusing the mix of tranny fluid that is coming out of the transmission? It would be a mix of 4 quarts new Lifeguard6 and some of the old. Less chance of too much new oil in an old tranny that has been posted about at a length.
4) With 212,000 miles, I already ordered the sleeves and bridge seal and will replace. Would you do the Sonnax Zip kit or solenoids if the unit is already out? Like I said, shifts great when upshifting or downshifting.
5) Anyone every have a service clone their TCM when buying a used transmission? Seems like even the independent shops have uneven cloned anything, only can use their SSD for new factory OEM unit TCM that are ready to receive the coding. Those are $2500 plus.