I don't know for sure but I don't think the diagram you sent is the right part. Would you know any place I could check for the part new or used.
I was not suggesting that the diagram I posted was the correct part/model for your Coach - just trying to show where the axle ID tag is typically located. You need to start with the axle "model" number (not the part number), So if you have the Dana/Spicer axle, you probably have the E-1320I or E-1320W.
If you have the Westport Axle, it looks like it is going to be the 13,200LB GAWR one (the F3W-1300 or the F6W-1300). Westport has two (the difference is the in axle drop (how much bend it has). See the photo below.
If you are trying to buy parts, you need to know "what you have" to tell to the sales guy.
Good luck