We have had several clients remove the OE fluid and install Amsoil, Mobil-1 ATF, ect.... This has been a problem.
Most the vehicles came back in with check engine lamps for
slipping transmission clutches.
I would recommend using the MB .6 fluid only.
The .6 trannys can be serviced, filter and all just like any other
auto.
I service my client's 5-spd autos every 60k and find people are ok with paying the higher cost.
However the fluid does it's job and can last a "lifetime".
Our Roadside wagon has over 145,000 hard miles on it and has
original fluid.
If you fill your car with aftermarket fluids and have a part failure
under warranty, you may be S.O.L. MB is now checking
oil samples and inspecting every failed warranty part.
I just had to submit a oil sample for a E55 transmission that self
destructed. Let's just hope the client did not change his fluid
to non MB products, or else he may have to pick up the tab.

DR.DIESEL