Trying to discover the additive to seal swell.
For engine oils and ATFs:
tris (C8-C24 hydrocarbyl) phosphite
Bis(2-ethylhexyl) phosphoric acid
and the azelamides such as:
N,N'-dimethyl-N,N'-dihexylazelamide, N,N'-dimethyl-N,N'-di2-ethylhexylazelamide, N,N'-dimethyl-N,N'-di-2-ethylhexylsebacamide
For brake fluids: IP
You can't go by odor to determine chemical makeup.
Quit sniffing that stuff or your brain will fall out!