It would be best if you just stick with what the
> manufacturer recommends. In this case, I believe
> the engineers probably know what they are doing.
>
> If you put gear oil in that trans, you might not
> like the shifting qualities when it gets cold.
>
> Ian
Yes, try to stick with the weight recommended by the manufacturer.
Still, you'll have to decide between the many brands which make that weight/grade of oil. >;^)
Come back to us with a weight recommendation and some folks here may have some more specific brand/type recommendations for you.
--- Bror Jace