Donald,

Like Richard said, Fluid and filter is okay. This is a young transmission for 128,000 Kilometers on it. What I would do is :

1) Replace the two o-rings in each solenoid. I believe Mercedes does not sell them(do not quote me). You may have to get the solenoid o-ring kit from a third party vendor. Because the "Golden Rule" all o-rings disturbed must be replaced-this is very true for criticle ones like Fuel injectors,torque converter, and these shift solenoids.

2) Since all 722.6's suffer from pressure leakage of the shift pistons, but 2 to 3 piston is the worst. The solution is to get a better seal, but the best practical way to fix that is from a third party vendor named Sonnax in the USA. They make a piston kit with o-rings for all the shift solenoids for about 70 USD

722.6 ValveBody Sonnax Kit Install.AVI - YouTube

Part Number 68942-05K

Sonnax - Aftermarket replacement transmission, torque converter, and high performance automotive parts[make]=11&filter[unit]=221

Sonnax - Aftermarket replacement transmission, torque converter, and high performance automotive parts

Download the valve body lay-out PDF

http://www.sonnax.com/downloads/valve-body-layouts/VBL-Mercedes-722-6.pdf

3) I would inspect each piston/sleeve assembly for broken springs

4) I'd measure the impedance of all the solenoids, and swap the upper shift solenoids with the lower solenoids as the video shows.

Hope this helps,

Martin