What type of rear end do i have? LOL

[hurlbird]

Owner of 68 Shelby. This is about my 70 MACH I sorry if this is unethical to ask in this forum. BUT my pinion in leaking and I don't have a tag and have enclosed some pictures to see if they help. I need to get the correct seal. Not looking for ratio insight. Thanks ahead of time! 

[Greg]

Go to Napa and tell them you need a rear end pinion seal.  They will fix you right up.  Also, go on youtube and look at "9" ford rear end rebuild" or "9" ford pinion seal installation" and you will learn a lot. 

[KR Convertible]

Check the yoke for a groove where the seal rides.  There are sleeves made to cover the groove and give you a nice fresh surface.

[hurlbird]

don't I need to know if it is a 8" or 9" ? Thanks

[hurlbird]

Sorry KR not following you....

[gt350hr]

   9" standard duty. The National seal number is 7044NA . They are the best there is.

[hurlbird]

Confirming this is a 9" correct? For my own knowledge what in the picture gives that away? thanks

[Bob Gaines]

Confirming this is a 9" correct? For my own knowledge what in the picture gives that away? thanks

The 9inch style pinion shield bolted in place is just one.

[hurlbird]

8" did not have that then? thanks

[68stangcjfb]

A full proof way of telling an 8-inch from a 9 inch. You can fit a 9/16 deep socket on all 10 nuts of an 8 inch. On a 9-inch, you can't get the socket on the bottom 2 nuts.

[Scode67FB]

As several have confirmed, it's a nine-inch.
Being a "Mach," it had to come from the factory with a nine-inch. Of course, over the 50 years of it's life, anything could've been swapped in.
Visually, as pointed out, the bolt-on pinion snubber is a giveaway. The eight-inch rears didn't have them. Also the socket trick on the bottom two nuts. On an eight-inch rear, you  can get a socket on the bottom two nuts. On a nine-inch, no socket fits. You have to use a wrench.

[hurlbird]

thanks for the clarification.

[KR Convertible]

Sorry KR not following you....

After 50 years of usage, the machined surface of the yoke can develop a groove where the seal rides.  There are sleeves that go over the area and give you a fresh surface and slightly tighter fit in the seal.  I was surprised to learn the seal number remains the same.  Prior to using them I thought it would be a lightly larger ID on the seal, but that has not been my experience.  Below is a link to one.  Please do your own research on part numbers, I just copied the first one I found.

https://www.randysworldwide.com/product/yms99181/

[gt350hr]

   The pinion retainer , the yoke , the case design , are my clues. As others mentioned the bolt on pinion snubber , instead of cast on , BUT there ARE 9" pinion retainers with cast pinion snubbers.

[hurlbird]

thanks KR. Seems like this could be a good practice when doing the job regardless. thoughts?