Right, I'm massively confused. I've been searching on here for AGES looking for recommendations for transmission/ gearbox oil to go in my 172 Cup. There are literally hundreds of threads on the topic, yet no definitive answers!! Anyone know Renaults exact specification and quantity (I assume it's an ELF product with a viscosity of 75W80)? I'll go from there thinking about an 'upgraded' solution if I need it... However, I've seen recommendations for: Elf Tranself NFJ 75W80 Elf Tranself TRX 75W80 Elf Tranself NFP 75W80 Elf Tranself TRJ 75W80 Castrol EPX 75W80 GL5 Fuchs TITAN SINTOFLUID 75W80 Millers Oils EP 75w80 GL5 Silkolene Syn 5 75W90 Motul Gear 300 75W90 (someone mentioned 75W90 "can lead to a baulky shift when hot due to the higher viscosity.")?? Some have also said the Tranself products are API GL-4, but API GL-5 is better? Which is better performing/ longer lasting, or is this subjective? Re: quantities - My search also showed that some people recommend using 4 litres, some say 3.5, others 3.1 and some 3?