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Technical Dana 44 rear end in a shoebox

Discussion in 'Traditional Customs' started by Big_Red, Jun 9, 2021.

  1. Big_Red
    Joined: May 6, 2011
    Posts: 23

    Big_Red
    Member
    from Fresno, CA

    Hey experts,

    I have a 49 shoebox, coupe, plan is to keep the flat head but go to an automatic. Just installed 3 inch drop springs in the back with new shocks. I’ve got a buddy with a Dana 44 that he doesn’t need anymore. He has it in his 56 pickup but put in a 9” to handle more horsepower. He says it’s 55.25”. I know the shoebox is something like 57. Would this rear end work with the eventual goal? What would be involved with swapping out the stock rear end to this one?

    It’s free but if it’s not a good fit I’ll pass. I know I’ll need different wheels later but already am planning on new wheels at some point so don’t mind that part.

    Thanks

    Red
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 55,931

    squirrel
    Member

    find out where he measured to get that number...if it's backing plate to backing plate, it might be a bit wide for your car?

    and the bolt pattern for the wheels will be wrong, as you know...they won't match the front, and 5.5" bolt pattern wheels usually look a bit different from 4.5" bolt pattern wheels.

    And the spring perches will need to be moved from above to below the axle, and spaced at the correct width, and set at the correct angle, just like on the rear you remove.

    And the U joint may be wrong. And the driveshaft length might be wrong.
     
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  3. miker98038
    Joined: Jan 24, 2011
    Posts: 1,143

    miker98038
    ALLIANCE MEMBER

    I have a Dana 44 in the back of my Thunderbird, came out of a truck somewhere along the way. It’s had 3 different gear sets for different engine/trans combination. They’re strong enough, but parts are getting difficult, and they’re a pita to work on. Mine had to be straightened, not unusual for one that was original in a truck. A free Dana might end up costing more than buying the right rear axle from a salvage yard.
     
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  4. Behind the flathead (especially with an automatic), I would keep the original rear axle. Unless it has excessive backlash, it will hold up fine. Good viable alternatives for that car is an 8" out of a V8 Maverick, 57-59 Ford car 9", or an 8.8 out of a Ranger Pickup. All are about 56.5" WMS to WMS. The Maverick rear is a bolt in after moving the spring pads in 3/4" on each side, and even the emergency brake cables work.
     
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  5. Casey Riley
    Joined: Jun 27, 2018
    Posts: 543

    Casey Riley
    Member
    from Minnesota

    I have a Dana 44 with 3.31's in my 51 Mercury flathead with the Merc-o-matic. Mine came from the factory this way.
     
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  6. 51504bat
    Joined: May 22, 2010
    Posts: 4,754

    51504bat
    ALLIANCE MEMBER

    Good info but only the earlier Rangers with 8.8's were 56.5 WMS to WMS. The later 8.8's were 58.5 WMS to WMS. I put a 8 inch Maverick in my '54 Ranch Wagon and yes even the emergency brake cables work.
     
  7. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,661

    Truckedup
    Member

    Doesn't the OP's car also have an original Dana 44?
     
  8. dwollam
    Joined: Oct 22, 2012
    Posts: 2,319

    dwollam
    Member

    '49-'51 Ford cars had drop out center sections, not Dana's

    Dave
     
  9. 51504bat
    Joined: May 22, 2010
    Posts: 4,754

    51504bat
    ALLIANCE MEMBER

    The wagons may have had 44's. My '54 Ranch wagon had a 44 while the cars had rear ends with drop out pumpkins. Could have been the same for 49-51 or not.
     
  10. vtx1800
    Joined: Oct 4, 2009
    Posts: 1,709

    vtx1800
    ALLIANCE MEMBER

    The 49 I had used a style similar to later Fords, NOT the Dana 44 (of which I have spend many curse filled hours:( If the width was correct you'd still have all of the questions that Squirrel asked. Free isn't always free..dang it.
    I think that @51404bat has it right. I'd forgot about Station Wagons as I have never had experience but many of the brake etc parts are different for the wagons.
     
  11. Maverick rear has always been a good swap. Problem is getting tougher to find in junkyards. Plenty strong (overkill) for a flathead and still has good parts availabilty. Plus has the correct 5x4.5 bolt pattern.
     
  12. Jeep.....if you can find one of the last of the Postal Jeep's from the 70's they ran a Dana 44 Posi and didn't get to much use. Still a different bolt pattern than 4 1/2.
     
  13. Hombre
    Joined: Aug 22, 2008
    Posts: 1,075

    Hombre
    ALLIANCE MEMBER

    For me I would find a way to use the Dana 44. These are damn good axles, and pretty strong as well. It came in Corvettes for many years and all E-type Jags since 1961, Jag used this rear end up until 1997. Thirty six years is a damn long run. In the Jag it was an independent rear but the center section was still the Dana 44. In your case it looks like the Dana is narrower than your stock axle but only by a couple of inches. That's around 1" per side, won't take much fabricating to make that work.
     
  14. 51504bat
    Joined: May 22, 2010
    Posts: 4,754

    51504bat
    ALLIANCE MEMBER

    Don't anything about the 44 you're talking about but the 44 I replaced in my Ranch Wagon (with a Maverick rear end) had a "Mechanics" or "Bat Wing" u joint. I'd never seen one before and I don't know if that will be an issue if it has one.
     
  15. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Some “close, but no cigar” misinformation in this thread. For instance, the ‘49/‘51 Merc sedans/coupes had Dana 41 axles (as did F1 pickups of the era), not model 44. The Ford and Mercury Wagons and some (maybe all, maybe 312 only?) ‘Birds thru ‘56 used the 44 axle.

    Jaguars were typically Salisbury axles, a very close cousin to a Dana 44, but had several internal dimensional differences that mattered.

    The 8.8 for Rangers were correctly stated as to overall width, depending on model year, but the pinion offset is greater than average, so driveshaft tunnel clearance could be problematic.

    As usual, @squirrel had the most comprehensive and correct information. The Maverick 8” seems to be the best dimensionally suited for a shoebox swap that doesn’t require a heavy duty axle.

    Ray
     
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  16. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    I read through all of the posts but still not sure as to the 'why' part of swapping...o_O
    What is the 'need' involved?
     
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  17. Hombre
    Joined: Aug 22, 2008
    Posts: 1,075

    Hombre
    ALLIANCE MEMBER

    Hnstray, Sorry there partner but no cigar for you either. Salisbury was purchased by Spicer in 1919, however in 1914 Spicer had been acquired by Dana. In 1929 DANA opened a Salisbury division in Toledo, Ohio. In 1970, the Salisbury Axle group was renamed the Spicer Axle Division.

    Few Jaguars used the Salisbury/Dana rear end which is almost identical to the Dana 44. They did use starting in 1961 with the E-type Jag use the Dana 44. Some were made using the Salisbury/ Dana but very few.
     
  18. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    That’s okay…I don’t smoke anyway…:D

    My comments were based on having read several posts over time that, in spite of their kinship, pointed out the detail differences between genuine Dana 44 marked differentials and their non-identical ‘twin’ in Jaguar applications.

    I readily concede I am not an ‘authority’ on either unit, though I have both, but have not attempted any parts swapping between them. However, those who have and reported their findings, along with photo evidence, claim significant, but not necessarily insurmountable, differences do exist.

    Ray
     
  19. Casey Riley
    Joined: Jun 27, 2018
    Posts: 543

    Casey Riley
    Member
    from Minnesota

    Not sure where where you're your information comes from, but the Dearborn plant was using Dana 44's in 1951 Mercs.
     
  20. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I can challenge your assertion on the same basis….”not sure where your information comes from…”

    Dearborn was not the only plant producing Mercurys in the era……I lived about two miles from the (now long gone) St. louis Mercury plant. But that proves nothing.

    What does matter is the casting mark on the differential housing that identifies the manufacturer’s designation of the axle model. 25, 27, 30, 35, 41, 44, etc. Several posts on this forum have ‘testified’ that the ‘49/‘51 era non-wagon Mercs , and F1 pickups were equipped with the model 41 axle, not the near identical appearing model 44. The 44 reportedly was used on station wagons (Ford & Merc) through ‘56 and likewise on F-100 and early ‘Birds.

    None of this really matters very much unless one is working on one of these axles and needs model specific parts. My ‘56 Studebaker Hawk has (verified) model 44 and my ‘60 Studebaker Lark has a (verified) model 27. All that and a $1.50 might get me a cup of coffee somewhere. But it has been HAMB tradition, and sometimes actually useful, to have erroneous information corrected. Sometimes the ‘correction’ is equally erroneous…….sorry I brought it up in the first place. :(

    edit: coincidentally, just yesterday i happened to read an article that said a sizable majority of people overestimate their own knowledge base…….apparently we all could benefit from a serving of ‘humble pie’ from time to time..:D

    Ray
     
  21. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    ...yeah, I've met a few 'experts' in my time and now with this www inter-web thing everyone wants to be one.
    IMHO, there is simply too much to know unless you are dealing with a very narrow field of endeavour.
     
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  22. squirrel
    Joined: Sep 23, 2004
    Posts: 55,931

    squirrel
    Member

    It's a good idea to look up the information to verify your memory, before posting.

    not many of us do that, very often.
     
  23. Dang......and I wasn't going to bring my Studebakers into the mix.....but why I seek out those mail Jeeps !
     
  24. Going back to the OP's original question, a good rear axle swap is determined by WMS to WMS, gear ratio appropriate for the swap, and parts availability. The shoebox Ford has narrow wheel wells, so WMS to WMS is critical, unless rims with special back spacing are used. The Dana 44 is a PITA to change the ratio, even if the parts can be found. As squirrel said, there is the different wheel bolt pattern. Ratio has the same issue for the original Hotchkiss design Ford axle, and gears are not available. But if the Dana 44 has the parameters that work for the OP, there it is.
     
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  25. flatout51
    Joined: Jul 26, 2006
    Posts: 1,209

    flatout51
    Member

    If you're keeping the flathead and going automatic trans then just keep the stock rear. The auto will be easier on the rear than a manual trans and you KNOW it fits perfectly. If it ain't broke don't fix it.
     
  26. MarcoITA
    Joined: Aug 2, 2022
    Posts: 2

    MarcoITA

    Hello guys,
    can anyone help me figure out what kind of axis is installed on my Mercury?
     

    Attached Files:

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  27. 51 mercules
    Joined: Nov 29, 2008
    Posts: 3,868

    51 mercules
    Member

    THe on
    My 51 Merc has a Dana 41.
     
  28. 55blacktie
    Joined: Aug 21, 2020
    Posts: 793

    55blacktie

    Many, many years ago, my uncle had a 50/51 Ford/w flathead and 3-speed manual transmission. He went through 3 rear ends.

    On the other hand, my mom had a 49/w flathead and 3-speed. No problem with the rear end, but she didn't hotrod.
     
  29. There is apparently multiple versions of this axle. I've seen references to Dana 41s and also 42 versions (used in mid-'50s Ford cars according to the context of the postings). Supposedly enough differences to foul up parts interchange if not paying very good attention. I know from personal experience that there are seal differences.

    Sorry, but @Hnstray has the right poop on the Jags. As an ex-jag owner, Jag used the Salisbury version far more than the 'true' Dana 44. I can't speak to the earlier E types, but know for a fact that by '75 Jag used the Salisbury exclusively except for a brief period when there was a shortage, and the Dana was substituted. These can be identified as per the factory service manual by their case drain (and vehicle serial number), a feature not found on the Salisbury. Note that not every vehicle in that sequence had a Dana, some did, some didn't.

    There were two main issues that precluded using Dana 44 gears in the Salisbury rear. First was Jag upgraded the ring gear bolts from 3/8" to 7/16". As the Dana didn't use that size until the late 2010s or so when Jeep introduced the Rubicon, fabricated bolt spacers were needed. I believe there's 'conversion' bolts now available. The other issue was Jag moved the ring gear mounting flange away from the pinion gear by .1" which required a special, Jag-only thicker ring gear. I believe this was done in '82 when Jag went to 2.88 gears for fuel mileage, but you better verify it. A few guys have fabricated blanchard-ground spacers to allow the Dana ring gear to fit.

    It is possible to swap ALL Dana 44 guts into the Salisbury housing, but it's an all-or-nothing deal. Here's the parts list needed for this.... Jaguar Differential Build (dazecars.com)

    I'll also note that the Jag posi unit (found behind all V12 motors and in the XJS) is a well-regarded unit. It's low bias so not really suitable for drag racing but is excellent for street use.
     
  30. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,440

    Boneyard51
    Member

    I think the “44” cast in the housing tells you! But with all this misinformation, who knows!




    Bones
     
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