Fiesta mk3 Gearbox

[Risbo]

Hi guys.
I have Fiesta mk3 1.1 HCS with carb
I had to remove halfshafts so now I have to change an oil in gearbox.

What oil do you recommend?
My local Ford shop don't have currently Ford oil and they offer me 80W Valvoline oil.
And also I can have Mobil mineral oil by similar price.
Mobil synthethic oil (75W-90) is around double price than that mineral so I won't take it.

I need your experiences.

For example, my brother changed oil on Skoda Felicia and put inside 90w oil - now he have problems with shifting when cold.

[mark frst]

i have always put in 80 done 20 plus box changes on fiestas never had any problems

[mercgrey]

i got some halfords stuff for my rs mate, seems alright!!

[dangerousdave]

Probably a bit late now but autodata says 3.1L of 75w/90 semi synthetic