Hot Rods Quick change question

I need to add lube to my Halibrand quick change and am looking for guidance on the best lube to use. And is it okay to just add more or should I drain everything and start fresh? Thanks for any comments. HFH?

 

Any 80 or 90 weight is good. When I was racing we use Lubrication Engineers 90 weight gear lube. It is red and stains anything it touches. However, it cuts down the gear temperature significantly. I'd watch guys in the pits changing gears and they would almost be smoking after a 10 lap heat race. It was all they could do to handle the gears. My gears were hot, but not too hot to handle. I still use it in my cars (non quick change).

 

Thank you!! And thanks for adding your great story.