they do make differential fluid (gear oil) but not manual tranny fluid. DO NOT USE ANYTHING WITH LIMITED SLIP MODIFIERS MEANT FOR THE REAR DIFFY IN THE TRANNY. Put MT90 or MTL in the tranny and be done with it.
Spee's view on Pinnacle Souveran:
"Next time, give me $70, I'll get you a decent wax and pull your balls through your left ear...same thing :-)"