My 1995 ford fiesta 1.6 lists sae80 for gearbox oil which seems to be mineral stuff.
Can i use synthetic 75w80 or will it blow up?
My logic is that if its a 80 when hot then it should be fine and thinner than the straight 80 when cold.
But not sure if gearboxs are more sensitive to oil than engines are?
1995 Ford Fiesta 1.6i 16v Si
2000 Toyota Celica 1.8 VVTL-i
2007 Toyota Aygo+ 1.0i