I have a 1949 3600 (3/4 ton) truck. I drained and removed the rear diff cover today and I have a re-fill question? I am not sure how to fill this rear diff? I guess I could pour it in the hole in the rear of the cover, but is that enough fluid?
Or, I also removed a fairly long bolt from the driver's side of the diff. It is about 4 inches long and threaded all the way. What is this bolt? Should I fill it from this hole, or the one in the rear of the diff? Also, should I use any special oil? Just a 90 weight gear oil?
