Hey farmboy555, I can't really recommend a specific type of grease - I know CAT has their own brand, however I understand it's a little pricey. Anyway, most hammers have a lubrication system now that is pump-to-point meaning there aren't any injectors or divider valves between the pump and the hammer. Here's the issue, if you want to call it that, with hammers and lube pumps. Everyone and their mother will recommend a grease with moly or some other solids for a hammer application. Thing is...solids prematurely wear components in the lube unit. In fact, we (I'm the Northeast Manager for Graco) don't recommend using anything with over 5% solids. Moly and other solids are used in case you're not able to constantly grease something, but with a lube pump you don't really need that since you're constantly giving the machine/hammer fresh stuff to work with.
Hope that helps a bit.
