What gear diff oil for KF?

[DynaMight]

Hi guys

Just got a KF and wondering where would be a good place to start with gear diff oil.

I do have a ball diff, but dont tend to have much luck with them, and I can almost anticipate needing to refit the gear diff at some stage The manual suggests 1000 or 3000cSt is an option.

I currently have 3000, 5000 and the treacle that came in the kit! I'll be racing indoors carpet in the winter and outdoors on grass/astro in the summer so not all high grip surfaces.

I guess what I'm saying is, whats gonna make it as close to a ball diff as possible?

Thanks