2 Stroke gearbox Oil

I got my hands on an old 1976 Yamaha DT125. What sort or gearbox oil should I use. People have mentioned Hypoid 80-90 or Automatic transmission oil.

i used to use 10w40 in my old rd 125 (same engine) will see if i can dig out the haynes for it


book well buried if no one else knows i will see if i can dig it out later

doh just re red it again mine was a later watercooled one