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Thought I Bought A 9 Inch Rear End

Discussion in 'The Hokey Ass Message Board' started by Low-Blow, Feb 7, 2011.

  1. Low-Blow
    Joined: Apr 6, 2009
    Posts: 229


    Well, I came across a Craigslist Ad today for what was said to be a Ford 9" rear end out of a 1963 Ford Squire Country Wagon. The guy was local so I ran over to take a look at it. I am not a guru when it comes to these things, but the things that I had been told to look for made me feel comfortable in paying what he was asking for it. I brought it home and began to research the tag information. The tag id is WBT AU 1, 3 50 3CB 100. If my research is correct, then I actually have an 8 3/4" rear end, not a 9". What are your thoughts? How does this rear end compare to the 9" how much less valuable is it?
  2. shinysideup
    Joined: Sep 1, 2008
    Posts: 1,627

    from ruskin, fl

  3. DE SOTO
    Joined: Jan 20, 2006
    Posts: 3,857


    If its an 8 3/4 MoPaR Rear end ...

    In my Opinion you have a Better rear end than any Standard run of the Mill 9" Ford.

    Never heard of an 8 3/4 Ford axle
  4. chaddilac
    Joined: Mar 21, 2006
    Posts: 13,867


    What Desoto said.... but show a pic!!

  5. coilover
    Joined: Apr 19, 2007
    Posts: 644

    from Texas

    If you can use a socket on the bottom two nuts holding the carrier to the housing it is NOT a 9 inch. If you have to use a wrench to remove then it IS a 9 inch.
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 48,290


    Ford called some of the early 9" rears 8.75" even though they're a 9" as far as we can tell.

    If it has a removeable center section, and you can't remove the lower two nuts that hold it to the housing using a socket (you need an end wrench), then it's a 9".
  7. Low-Blow
    Joined: Apr 6, 2009
    Posts: 229


    Pictures attached.

    Attached Files:

  8. 117harv
    Joined: Nov 12, 2009
    Posts: 6,590


  9. I have been through this before. Bought a rear end I thought was a 9" but the ring gear measured less than 9". Everything looks the same from the outside. I'm sure if you know how to read the tag the info is on there.
  10. Low-Blow
    Joined: Apr 6, 2009
    Posts: 229


  11. barnescole
    Joined: Dec 2, 2008
    Posts: 138


    It's a 9".....i have the same in my truck, it is the older (and slightly weaker housing) is the pinion seal leather?
  12. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,919

    seb fontana
    from ct

    An 8-3/4" is for all practicle purposes a 9"..Only real difference is the ring gear bolt size, 7/16 vs 1/2..A 9" carrier can be used with an 8-3/4" ring gear but the bolts are special with a 1/2" dia shoulder for the 1/2" holes in the 9" carrier..Whole chucks can be interchanged..There is also a 9-3/8", not much in perf gear but a 9" chuck will interchange..As long as axle splines match carrier splines your set..
  13. 32fivewindow
    Joined: Mar 22, 2008
    Posts: 226

    from USA!

    That is a 9". Looks like it has standard large bearing ends and is the weaker of the cases.
  14. 8-3/4" is the standard Ford diff that was used in Australian Xw-Xy Falcons, they were also used in some Mustangs. They are considered a 'Light duty' rear end and are weaker than a 9", but unless you are going to put some serious Hp through one it should be fine.
    I have heard that there is not a good range of ratio's available.
    I ran one in my old A RPU, had a bog stock 302 and that diff was fine never had a problem with it.
    Pretty sure thats not one though.

  15. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109


    But wait! There's more!

    The housing is only clearanced for the 8 3/4 ring gear. You will find that the carrier is 28 spline and is not bored large enough to permit use of 31 spline axles. (later units would allow 31 spline if you swapped ou the spider gears or used a mini-spool, etc.)
    The carrier will not support gobs of power, so any upgrades usually involve tossing the entire center section for a later unit. To get a later 9" unit to go into the housing, you will need to grind clearance in the mounting flange where the ring gear passes through the hole. Once it's in, there's no concern, but it won't go in without a little grinding.
    Last, be gentle with all the brake parts. They are dang near impossible to replace. There are only one or two options for small bearing drum brakes and most anything else requires changing the housing ends.
    In short, it's a good value if used as is. After that, it's an expensive way to get a 9", but the round back is usually very sought after by guys that will have it visible under their early hotrod.
  16. RAY With
    Joined: Mar 15, 2009
    Posts: 3,133

    RAY With

    Pictured is a Ford 9 . If its an actual out of a Station Wagon unit it has the 88128 axel bearing and large axels and is a good unit. There is a huge selection of ring and pinion gears on Ebag from NASCAR sellers if you look and price is right. It should also have the large brakes and parts are still available for it.
  17. bulletproof1
    Joined: Feb 23, 2004
    Posts: 2,080

    from tulsa okla

    also notice the only way to fill the axle with grease is through the housing (no fill hole on case) you can drill and tap for a plug if you put it in another housing,,,
  18. AllSteel36
    Joined: Jul 20, 2009
    Posts: 562

    from California

    Wht can't you fill it through the plug in the rear?
  19. If it is the early ('57-'59) rear it is indeed an 8 3/4 rear. I don't have a list in front of me so I can't tell you what it is. But if it is a smooth back it is a '57 and if it had dimples it is a '58-'59.

    The upside to that is that the 9" chuck goes right in no problem. So just fond a 9" chuck and you are good to go.

    There is some information and pics on this thread.
  20. chop32
    Joined: Oct 13, 2002
    Posts: 1,077


    I know for a fact that a later 9" "chuck" will not fit in a '57 housing without some clearance grinding of the mounting surface for ring gear clearance.
    '57 (and I believe '58-'59) dropouts had a ring gear that was less than 9" in dia, whereas the later units were a true 9" dia.
  21. Deuce Roadster
    Joined: Sep 8, 2002
    Posts: 9,519

    Deuce Roadster
    Member Emeritus


    Just get a new gasket and put it up to the housing. Mark the spot that needs clearance and grind away. Then any 9 inch center section can be bolted in. No big deal.

  22. Bolted a late chuck in a '59 case last year no grinding. Maybe the '57 had a thicker flange. Ford used an 8 3/4" ring through '59.
  23. titus
    Joined: Dec 6, 2003
    Posts: 5,074


    Is it a good gear ratio? if it is then use it, who cares if its 9" or 8-3/4, it does the same job, if your gonna rebuild it it uses the same parts, so what does it matter??

    And if the ration isnt what you want just get a newer carrier, then they dont have the stupid big diameter pinion seal.

  24. Low-Blow
    Joined: Apr 6, 2009
    Posts: 229


    If the tag is correct (and the website I listed earlier is correct), then the ratio is 3.50 and it is out of a '63 Passenger Wagon.

    To everyone who has chimed in on this topic, I really appreciate the information.
  25. If it is out of a '63 wagon it should be a 9" I wasn't aware that they were still using the dimple housing past '59.

    Never the less you should be alright.
  26. I put a 62 chunk in my 59 housing with no grinding.
  27. Stan Back
    Joined: Mar 9, 2007
    Posts: 968

    Stan Back
    from California

    Don't trust the tag. Count the teeth.
  28. chop32
    Joined: Oct 13, 2002
    Posts: 1,077


    May just be the '57 housings...
    I know that nothing spices up your under car vocabulary more than finally getting the 3rd member wrestled into place just to find out that the ring gear wont clear the housing!!
  29. kein
    Joined: Oct 28, 2007
    Posts: 199


    Great thread. I was wondering the same about what is on my car and now I can verify with the help of everyone that wrote here.
  30. T Achilli
    Joined: Aug 25, 2009
    Posts: 239

    T Achilli
    from walworth

    Yes.... Good info, I have a 59 T-Bird 9" I am gonna use.......Whats the difference in brakes, t bird rear is missing all hardware and drums but i have another later set. is it just housing end pattern?

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