So here it goes... another oil thread. However I am just here to report what i found and learned from lots of reading, research, and trial in my own 2011 RRS.
For some background, I recently picked up a 2011 RRS SC with 130,000 km on it. It has seemingly been very well cared for by someone who understands how these vehicles work. I did not really have transmission problems at all. There was maybe a very quiet noise from the torque converter once when i took off from a stop fast.
I decided just for longevity that i would replace the fluid, pan, and filter. Turns out someone was ahead of me and the previous owner changed it already too. The fluid looked very new. I already had the pan off and didn't plan to stop as i stripped the plastic drain plug and had a new pan in front of me. I decided on Amsoil over the recommended Lifeguard 6 fluid. The decision was not because of the price difference, but because I read about these transmissions having what seem to be fluid related problems from time to time. A few people went out of their way to get an oil analysis done on their Lifeguard fluid and have found how bad it proved to be, only staying in its spec for around 30,000km.
So I decided to take my gamble on non approved fluid and trust that Amsoil knows what they are doing here. I filled the transmission pan, removed a cooler line, placed the line in a container with a mark at 2L to not run the transmission dry, had someone help me so I could start the engine and then stop it when fluid hit the line, then replacing the lost fluid from the pan. This would make sure most if not nearly all of the old fluid was out.
After that, i drove around for a while noticing the vehicle feel freer or more responsive with shifts so smooth i couldn't really tell when they took place. I drove for a while carefully to prepare the fluid for the next step (the fluid will wear in and its friction properties will change when some clutch material gets in it)
I stopped and reset the transmission adaptation. This is a different fluid. While compatible, still different. I spent a very long time driving through the recommended relearn procedure just repeating driving up through the gears, coasting to a stop, holding the brake for 10 seconds. The transmission is always in learn mode and anytime you come to a stop holding the brake for 10 seconds, the adaptation values change. This made it feel like a new transmission as far as i am concerned.
I am by no means saying that I know amsoil is truely safe in these boxes long term. But I feel it is a better fluid,that it is safe, cheaper (and that can also mean more frequent drain and refills), and I also feel that the computer has the ability to adapt to the slight differences in this fluid and would not let the clutches slip and destroy themselves unless you did the relearn improperly.
I will be happy to report back with what i feel as the KM goes up and it sees more use. I may also send it in for an analysis to see how it is doing.
PS: We also own an audi with a zf box now running this same fluid and for 10,000km it has been smooth and completely problem free. I actually did not do an adaptation reset. I probably should and will.
PSS: We also have had two toyotas that use a "special" fluid that have had the transmissions working incredibly on this fluid. One had probably its first fluid change ever at 250,000km and it resulted in no issues.
I would like to hear if anyone else has been brave or crazy enough to use something other than the Zf recommended fluid.