[W126 Coupe] TRANSMISSION FLUID LEAK

[Soy Medina]

Hi,

I have this slow leak coming from my transmission and it seems going out 
through the seals. I barely used the car, about once every 5-6 weeks.

There is also a slight leak from the engine.

My mechanic is saying that I should used the car more often so that the 
seals will not harden and thereby leak oil or fluid. Is this correct?

Is there any way that you would suggest to reduce this leakage aside 
from rebuilding the engine or transmission? What about oil seal 
treatments, i.e., additives?

I would appreciate any advice that you can give.

Thanks and may all have a Happy New Year!

Soy Medina
SEC 560 1989