That's interesting Phil as I understood that many other gearboxes that ARE specified EP oil use baulk ring syncromesh, such as the T2 VW I ran for years and also more modern vehicles. So presumably it isn't the actual principle of the way the baulk ring works that necessitates the use of engine oil in the Austin-derived Minor box?philthehill wrote: ↑Thu Nov 23, 2023 5:20 pm The last thing you want on a Minor gearbox synchro baulk ring is extreme pressure oil. You need a oil that is quickly cleared from the baulk ring.
Everything else in the Minor gearbox can cope with EP oil.
I know that additives in some EP oils such as GL5 can damage the phosphor-bronze components in older gearboxes.