A833 fluid

I use that Stalube as well. I'm actually having trouble finding it. Do you know if they still make it?
Go to this page and click on the "Where To Buy" button. It's showing in stock at Grainger outlets in my area.

https://www.crcindustries.com/api-gl-4-multi-purpose-gear-oil-1-gal/
It's a small demand item, so it could be discontinued. Or possibly a batch blending wasn't scheduled soon enough to keep wholesalers and retailers from running out. You could contact CRC and ask them.