Morris Minor Owners Club

so far from previous threads i have leanrt that in my gearbox i need 10-40 if its in good shape or 20-50 if in not so good shape, its just been rebiult so im assuming its in good shape! as long as i use a decent quality engine oil does it matter if its mineral or semi synthetic?

Just use mineral 10W40. All this 'semi-synthetic' nonsense is only for modern cars with very close tolerances. For your engine - ASDA 20W50 is fine.

i have some of the 'classic' comma engine oil in 20w50 this would be ok also then? in previous threads it was stating that 10w40 gives better economy? which was why i was going to go for it but you reckon not?

10w40 is good as is 20w50. it depends what you have to hand really.

i have spare 20w 50 but dont want to chuck it in just cos i have it i would rather put in whats best for the box

well in that case, follow the advice of the moggy Oracle and use 10w40. if its good enough for him then its good for your gearbox

Yes 10W40 if it's a good box - that will cause less drag and better economy. But 20W50 for the engine!

so you'd put semi synthetic in a 50 year old gearbox?

i use that in my new car. in the 803 i use 20/50 in the engine and box. never had a problem in years