DS5 Auto Box

[GiveMeABreak]

I suggest you don't go any further until you understand what your friend actually has. Forget ATF AW-1 that's for full automatics with a torque converter. Your friend does not have an automatic, but a piloted manual gearbox (standard manual gearbox and clutch with hydraulic actuators to do the shifting and clutching operations).

The level at just under the MAX is fine and I seriously suggest you leave this well alone if there are no issues as these are very complex systems that require the use of professional diagnostic equipment to diagnose and for maintenance. The hydraulic actuators also use a special oil specific to this system, so don't put ATF anywhere near it. The system also has to be depressurised before the special actuator oil is both read and topped up, and the system re-pressurised afterwards.

[Mares]

Update: oil and filter changed, output speed sensor replaced, gearbox is working fine with no issues, problem solved.