Dig unto the Dexter website and you will find a section:
https://www.dexteraxle.com/resources...s/hub-hub-drum
Then go to Hub & Hub-Drum then their instruction sheet which will then give you a grease spec. If you dig into that website, there will be some actual grease manufacturer's recommendations. I'm using a Mystick product though which we in the US can find at Tractor Supply.
You do need to follow that grease spec as, IMHO, the 'bearings used by Dexter are Unfortunately, pretty marginal in size for the weight then using marginal Chinese bearings makes it worse. I've switched to US made Timkens though all of them are not US these days but seem to be as good
Dexter doesn't make it as easy to find info since Lippert bought them and modified that site - but it's there and you just need to have patience.