Open the fill plug and dig around to see what the consistency is of what's in there. It will likely be closer to a solid than a fluid.
I dug as much as I could out through the fill hole, then filled it with new grease. The small amount of crud which you cannot remove will mix in with the new grease, or stay put and out of the way in the small nooks and crannies.
Carl


1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission