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Dana 20 To Dana 44

Discussion in 'Early CJ5 and CJ6 Tech' started by hunter blacksmith, Nov 12, 2019.

  1. Nov 12, 2019
    hunter blacksmith

    hunter blacksmith Sleepin’ Jeeper

    Valley springs,ca
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    Hey guys,
    So.... I’m building my first Jeep (1962 cj5) as a gift for my dad. Right now it has a gutless f134,t90a, and a Dana 18 with a 3-3/32” bore. I have a mildly rebuilt amc 304, T150, and a Dana 20. My only problem is that the rear axle is an offset 44 and the Dana 20 is center output. I do not have a lift so the driveline angles are very slight. I think it would be okay. What say you?
     
  2. Nov 12, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    Is the issue that the T150 won't mate to the smaller bore D18 - needs a 4" bore? Otherwise I would use the D18...that rear driveshaft is so short, that even without a lift, the lateral angle between a D20 and offset D44 would still be significant. I am sure its been done before, and depending on usage, it may have even worked fine. IMO, I wouldn't do it. I like the option of an OD on a D18 with the T150, and ***uming you have something like 4.88 or 5.38 gear ratio in the axles, the OD would be helpful at higher speed. You could also consider a centered D44 from a 72-75, bolts right in, but you would probably have to deal with changing the gear ratio, either in the rear to match the front, or rather, change the front to match the 3.73 rear and the need for an OD begins to fade.
     
  3. Nov 12, 2019
    hunter blacksmith

    hunter blacksmith Sleepin’ Jeeper

    Valley springs,ca
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    1.The problem is that the T150 has an output gear that has a machines seal surface and the gear is not compatible with any T18’s. 2. The problem with changing the rear axle to a center output 44 is that the later center 44’s are wide track (5” wider than what I have). 3. I already have 3.73 gears so no need for an OD.
     
  4. Nov 12, 2019
    hunter blacksmith

    hunter blacksmith Sleepin’ Jeeper

    Valley springs,ca
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    I’m just trying to make an every day driver. Not a major off-roader. So there will not be any binding issues.
     
  5. Nov 12, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    I can't help you with the the T150/D18 issue, but the intermediate 72-75 D44 are centered and are narrow track and flanged, one piece axles. They are direct bolt in replacement for the early tapered D44, stronger that the tapered set-up, and most of them came with 3.73 gears. I like the D20 as its 'quiet' compared to the D18, and the 72-75 cj5s came OEM with D20/NTcentered D44
     
  6. Nov 12, 2019
    hunter blacksmith

    hunter blacksmith Sleepin’ Jeeper

    Valley springs,ca
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    Really? They came from the factory like that? I didn’t know that.
     
  7. Nov 13, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2020 Sponsor

    Denver, CO
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    keep your eye out, they are around...post a WTB in the classifieds....
     
  8. Nov 13, 2019
    Norcal69

    Norcal69 Out of the box thinker 2019 Sponsor

    Northern California
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    You need either a postal axle or a 72-75 Cj5 axle.
    Watch Craigslist and Facebook market place. I wouldn’t spend any more than $200 for one unless it had the correct gears. I went from a d18 to d20. Night and day difference on the highway!
     
  9. Nov 13, 2019
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    If there is no lift, you can get away with the mis-alignment between the D20 and the offset rear until you find a proper axle. The T15/D20 setup is short enough that the angles aren’t too severe - again, as long as the height is close to stock. The only issue will be having to possibly make or buy a shorter rear driveshaft when you do find the right axle.
     
  10. Nov 13, 2019
    Jeepsterjim

    Jeepsterjim New Member

    Lincoln, CA
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    Apr 25, 2019
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    commando has a d-44 narrow track
     
  11. Nov 13, 2019
    garage gnome

    garage gnome Rust polisher

    Western MA
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    I wouldn't run a D20 with the offset diff. I had a jeep like that once and it ended up blowing the rear bearing apart on the D20 from the side loading caused by the driveshaft.
     
  12. Nov 13, 2019
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    No, the driveshaft is too short to use the Dana 20 and offset Dana 44 axle. It will quickly break. You must pair an offset transfer case with an offset axle, or no offset for both.

    The 304 can be fit in there, but I would not do this swap for two reasons. First, you can buy a '72 or later CJ-5 with a 304 and 3-speed pretty easily, and you get many other improvements such as better axles, better brakes, better steering ... it just does not make sense to build a Jeep with a 304. The '72-75 models in particular have few differences from the earlier ones, aside from these upgrades. Rule of thumb - it will be easier, cheaper and have a better result to buy the vehicle that you want rather than build it. Always worthwhile to seek out what you want, even if you have to travel to get it and pay a premium price.

    Second, I would use an engine that's easier to fit in the engine compartment, like the Buick or Chevy V6s. Donor vehicles for the Chevy V6s are cheap and plentiful. Lots of discussion here if you search and read old posts.
     
    Last edited: Nov 13, 2019
  13. Nov 13, 2019
    Twin2

    Twin2 wasn't me 2020 Sponsor 2019 Sponsor

    Virginia Beach, VA
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    now if your going to keep running the Dana 20
    just get a AMC NT20 rear . still find them in junkyards here
    everything else gets took
    still need a gear change
     
  14. Nov 13, 2019
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    A driveshaft’s u-joints don’t know the difference between sideways misalignment and up/down misalignment. Nobody seems to have an issue with adding a lift kit on an intermediate, and this would be around the same misalignment, just sideways instead of up. I wouldn’t call it a permanent solution, but to get by until the proper rear is found while working out other bugs.
     
    Steve's 70-5 likes this.
  15. Nov 13, 2019
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    Only the '72-75 CJs will bolt in and be centered. All the other options (Commando, later CJs) have spring pads in the wrong place (outboard) and you'll have to weld new pads onto the axles. They won't have the right ratio.

    Re the offset, even my factory new '73 CJ-5 with a 304 and 3-speed threw the rear driveshaft in about 20K miles. No lift, the "heavy duty" suspension. And I'm not convinced that offset in two planes is equivalent to offset in one plane. Think I read on the TOm WOods site somewhere that offset in two planes is particularly bad.
     
  16. Nov 15, 2019
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    actually they do. Gravity and other factors play into this.
     
  17. Nov 16, 2019
    ITLKSEZ

    ITLKSEZ Volvophilic

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    Please elaborate.

    If the trans output shaft and pinion follow two lines that would never intersect in space (parallel), how would the u-joints know at what degree they are clocked? The total degree of misalignment each u-joint is experiencing is equal and opposing, whether the shaft is clocked at 0 degrees (vertical, from up to down) or 90 degrees (flat, from left to right). Regardless of what direction the shaft points, the yokes are still on parallel planes. How would gravity (or?) have any measurable effect?
     
  18. Nov 16, 2019
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    What you say sounds great on paper and would probably be true IF u-joint angles stayed static but they are dynamic. They constantly change with suspension compression and rebound, spring wrap (pinion angle changes), and the arc described by the rear axle in leaf sprung vehicles as the suspension cycles. These are hard enough to compensate for in one plane. Add in the second plane and u-joints simply don’t like it. Gravity has an effect on the alignment on the needle bearings in the joint. Obviously centrifugal force has an effect as well but gravity helps keep the needles aligned to certain degree. Take that away and the needles like to bind inside the caps and on the trunnions.

    There were some vehicles like Willys Wagon, pickups, Wagoneer, etc. that came from the factory with a bit of an offset between the transfer case and rear pinion, but in every case they were longer vehicles with a long (relatively) driveshaft. In these cases the driveshaft length and mass was able to absorb the vibrations created. The short driveshaft in a CJ simply cannot do that.
    I’ve been in the automotive industry roughly 33 years, 21 years of that in the four wheel drive industry specializing in drivetrain, steering, and braking systems. In all those years I’ve never seen a short wheel base vehicle with an offset driveshaft successfully with no vibration problems. I think the manufacturers figured it out long before us which is why they keep the driveshaft lined up.
     
    timgr and colojeepguy like this.
  19. Nov 16, 2019
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    I guess we’ll have to agree to disagree in this one. I never said it was ideal, specifically for the alignment variables through use, but the moments in time when the variables occur are not the majority.

    My point was, there is no difference if the shaft is misaligned sideways or up/down. If the OP were to misalign his shaft 20° sideways, or install a 6” lift that points his shaft 20° down, the U-joints are still working at an angle that is beyond the recommended limit, and it shouldn’t be a permanent solution. And is why I recommended it as a temporary option until they find a centered rear.

    Of course manufacturers keep the angles near-straight and within check. I’m not sure why they would angle it when they have the option to run it straight?
     
  20. Nov 16, 2019
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    They won't have the right ratio, except for maybe the '72-75 CJs with 4.27 ratio which may match the '62s ratio. Some F134 CJs came with 4.27s. Likely the '62 has 5.38s though, and any replacement axle will need regearing.
     

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