Here’s a concise answer:
It seems you're asking about in the context of hydraulic fluids or tractor transmission oils. hcf-2 equivalent
is a Hyundai/Kia specification for automatic transmission fluid (ATF) used in their 6-speed automatic transmissions (specifically the A6MF1, A6MF2, etc.). It is a low-viscosity fluid. Here’s a concise answer: It seems you're asking