I had the car recently inspected, esp. for what I believed to be a tranny fluid leak. Reason being, I find minor residue of leaked fluid under the central area of the car, only once it sat there for 2-3 weeks.
Mechanic says he can't see anything, where it possibly could leak from and tranny fluid level is where it is supposed to be.

He noted the SLS fluid level to be low. I found the part # for the Febi ZH-M hydraulic fluid in another thread. Thank you.
I'll be getting 1 Liter of it to top of the reservoir. I am reading the W124 SLS does not use the same fluid as in the PS system.

First and foremost, I'm trying to find out what is leaking while the car is parked for a few days. Could that be SLS fluid I find under the car in the proximity of the transmission?
Ps, suspension is great, very smooth ride. The air accumulators have been replaced a few years ago.