I’ve just replaced the rear diff gasket, and am about to fill with fresh fluid. I have the Haynes manual, image below from the differential lubricant types and capacity page. By checking my VIN number, I know I have an ‘anti-spin differential rear axle’. It’s a Dana 70.
Question: Do I need to add 8 oz of limited slip additive? I was told to, but the manual seems to indicate not?
TIA for any advice.

 

Some bottles of lube will already have the additive in it, and will say so on the bottle. If it doesn't, it ain't there, and yes, you need it.