Tran and LSD Diff fluid choices?
 

Ok, I've got an 85 GSL-SE and I want to change the manual transmission fluid and the rear differential fluid.

Any recommended gear oils? Which ones will I need to add a limited slip modifier to in the rear diff? Where do I get the limited slip modifier and how much do I use?

Redline and Neo oils both have the modifier. Redline MT-90 for the tranny, 75W90 for the diff. I've heard good things about Royal Purple, but never used it. Neo is what I'm using now (in my 3rd gen).
~Tom

I'm thinking about trying Castrol Hypo C 80w-90 for the trans and rear end. Anyone see any bad complications/results with that? That's the weight mazda recommends in the 1st gen for my temperature climate.

I just put NEO in my FD recently. The tranny feels slightly smoother when cold then the Valvoline I had in there, but the diff showed a nice improvement in slow corner exits at the track. I like the stuff.