200-R4 Transmission fluid

[Track T-4]

I just finished replacing the leaking pan gasket on my 200-R4 transmission, now for the fluid. The trans has a mild shift kit. There is an external cooler so I probably did not drain alll of the fluid. I do not know what type/brand fluid the previous owner used in the transmission so a little concerned about the potential for switching to something different. Two questions:
1. If the fluid was synthetic before, what are the ramifications of switching to regular fluid and vice versa?
2. What is the best fluid to use in this transmission?

Thanks,
Bruce

 

[railroad]

You could go with something like Red Line, B&M, etc. They are supposed to compatible with all other fluids and be better, per advertised. Short of that, go with what is on the dipstick. Good luck,

 

[Screaming Metal]

What RR said!