In reply to the other post where you stated you were confused.
http://www.fordpinto.com/general-help/rear-end-by-loner-(reply-to-locked-thread)/msg175065/?topicseen#new I'm not sure what has you confused? But, I will basically restated what I said before incrementally.
1. There were two different rear ends used in Pinto's.
2. One type is the 6-3/4" which sounds like what you describe. There is a removable rear cover. However, a picture would be helpful to decide that is actually what you really have. Or, you can do a Google image search.
3. The other type is the 8", it has a smooth rounded cover that is not removable and the gears are accessed by a section removable from the front.
4. There are no specific Pinto parts dealers like there might be for a classic Mustang or Camaro. There are a few individuals that sell parts they have acquired. Asking specifically here would be a start but frankly this board has very low activity. So, you may not get any response, or it may take some time.
Update - Case in point: 48 hours have passed (see image) since I replied to your initial, locked post with a separate post..., Dewayne the Administrator then unlock and moved your post and I have re-answered your post at this new location on the Forum. In that 48 hour time period the three most recent posts are all three of those actions. Like I said, it can be slow.5. It is likely difficult to find someone just selling the axle or spider gear.
6. You would probably more easily find someone selling a whole 6-3/4" rear end but that is a heavy item and costly to ship. If you let people know where you are located (in general) you have a better chance of getting a reply if they know you are near by.