Tandd --
Us folks with Freightliner Custom Chassis have oil filled front hubs so can't help you much with your question. I didn't realize Holiday Rambler used grease filled front hubs until seeing your post and looking at your owner's manual which is available from the HR website -->
https://www.holidayrambler.com/owner.../owner-manuals
When I have questions such as yours, I call Newmar's Customer Service Department and they are very responsive and very good for providing the parts information I need.
Have you tried contacting HR for part numbers and potentially purchasing parts from HR -->
https://www.irv2.com/forums/f24/fron...ce-530634.html
Do you have an HR dealer near you that could also provide part numbers / parts you need?