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Ujoint small vs. Large Debate.

Discussion in 'Early CJ-5 and CJ-6 Tech' started by jpflat2a, Oct 28, 2009.

  1. Oct 28, 2009
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
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    yep
    V6 used the smaller diameter yokes and u-joints on the front shaft only.
    this means smaller diameter yokes on the D18 and D27 as well.
     
  2. Oct 28, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    That's rather odd that the larger motor would use smaller joints.


    Edit: U-joint data now posted.
     
    Last edited: Oct 29, 2009
  3. Oct 29, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    Not when that larger motor needs more driveshaft clearance because it's, well, larger.
     
  4. Oct 29, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    That has a whole lot of nothing to do with the size of the u-joints or yokes. Think about it.
    Posted via Mobile Device
     
  5. Oct 29, 2009
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
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    Re: 1966 CJ-5 front driveshaft

    :?
    crawl under a stock V6 Jeep
    look at how close the driveshaft is to the bellhousing and starter.
    then think about it
     
  6. Oct 29, 2009
    nickmil

    nickmil In mothballs. Sponsor

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    Re: 1966 CJ-5 front driveshaft

    I've got two front drive shafts with the smaller yokes. One from a '67, one from a '70. Both stock,both V-6 powered Jeeps. Have a stock '71 at the shop also a V-6 powered Jeep with the smaller front jointed shaft. They needed more clearance therefore the joints needed to be smaller for clearance as mentioned.
     
  7. Oct 29, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    I did think about it. That point is not where the yokes are located. The rear yoke is about halfway up the side of the trans and behind the bell and starter, and the front yoke is ahead of the oil pan and nowhere near the bell or starter. Smaller joints don't relocate the driveshaft's axis farther away from the motor in space. Moving the pinion outboard, moving the D18 front output outboard, moving the motor to the driver's side, redesigning the oil pan, or reducing the OD of the driveshaft tube would increase the clearance at that spot. Not changing the joint or yoke size.

    Who has a link to the dimensions of the two joints that are possibilities here so that I have a reference for when I get home to measure the cap width?
     
  8. Oct 29, 2009
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
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    Re: 1966 CJ-5 front driveshaft

    link ?

    the 297X ujoint measures 2.97" in width
    the smaller measures 2.20" in width

    and..just so you know
    in Jeep CJ series
    all propeller shaft ujoints are the same from 1941-1986
    with only two exceptions:
    1) the V6 front driveshaft; they are smaller diameter as noted above
    2) the ujoints in a TH400/Qtrac front CV driveshaft.

    Technically, the u-joints in the CV shaft are the same dimensions
    the difference is the location of the needle type zerk fitting
    located either in the body, or in one of the ends caps.

    good luck with your sale
     
  9. Oct 29, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    Well, its definitely not a 1310. That rules out the 297X/760.

    Just for nomenclature clarification, CJ's (and FSJ's) didn't use constant velocity joints on their driveshafts. You're thinking of a double-cardan joints. A CV joint is something else.
     
    Last edited: Oct 29, 2009
  10. Oct 29, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    FWIW, as I recall, the small joints came about to clear the TH400 on the Commando. It apparently carried over to the CJ V6 for some reason, possibly just because Kaiser had purchased a number of the joints/ shaft yokes from Spicer.
     
  11. Oct 29, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    We have it covered, man. If you check the timestamps, this all took place today. I said I'd measure it and I just made it home from work a little while ago. I don't play games when it comes to part sales:

    http://www.greatlakes4x4.com/itrader.php?u=78 Nothing goes anywhere until people know what they are getting. :beer:



    Annoyingly enough, I found two different part numbers for the u-joints. The May 2008 Spicer PDF K350 catalog I have says that it should be a 5-153x according to the application. So does the online version of the K350 catalog. I think this catalog has some serious issues, as its calling out the same joint on the driveshaft all the way through the 1986 CJ-7.


    The Dana "Identify Part by Dimension" website says that its a 5-105x by the numbers, which I verified with a caliper:

    K1) Snap Ring Dim. 1.718
    D1) Bearing Cap Dia. 1.000
    K2) Snap Ring Dim. 1.718
    D2) Bearing Cap Dia. 1.000
    OEM Mfg. SPICER
    OEM Series 1100

    Novak is showing the TH400 not being used behind the V6 until 1969. If that is correct, the small u-joints pre-date it. Most sites say that the TH400 was optional on C-101's behind the V6, but do not specify a year range. I can't seem to find any references on Google to a TH400 being used on a C-101 before 1969, but I did notice some Wanted ads looking for 69-71 C-101's with a TH400 (which corresponds with Novak's info).

    But again, changing the joint size doesn't relocate the driveshaft's axis in space. You would need to move part surfaces or change shaft diameters in order to achieve that. I think its much more likely from an engineering perspective that the small joints came about on V6-equipped CJ's in order to provide a functional fuse in the driveline to provide a more easily repaired failure and protect against breaking D27 gearsets now that a more powerful engine with a heavy flywheel was in the mix. Spin it up, dump the clutch, and pow - broken D27 gears. When the stronger D30 was rolled out, the small joints disappeared, correct?
     
    Last edited: Oct 29, 2009
  12. Oct 29, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    No, but it is smaller in diameter which would give more clearance on the side of the trans.
    You're right though, the CJ's had the small joints with the introduction of the V6 in 1966.
     
  13. Oct 29, 2009
    DanStew

    DanStew Incorrigible. Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    It doesnt change the shaft axis, but the ends of it will not be as large. Think of it as a tube with two baseballs on each end. change the baseballs to racquetballs, but not the shaft. The shaft remains the same diameter, but the ends are now smaller and have more space to the sides.
     
  14. Oct 29, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    Yeah, I understand that. I don't think you guys get where the clearance concern lies. The yoke area is not where the clearance is at a minimum.

    Look at this T90/D18. The yoke is nowhere near anything. In theory, there would be even more room when talking about a TH400/D20, as the yoke would be even farther away from the bell. Clearance to the trans, bell, motor, or starter becomes an issue along the shaft, not in the area of the yoke.

    [​IMG]
    [​IMG]

    Here are more showing the fore/aft location of the yoke, how far away it is from the bell, where parts get close together on the shaft of the driveshaft, the vertical distance between the front output and linkage and the clearance around the larger yokes.


    [​IMG]
    [​IMG]
    This last one is difficult to see due to the angle, but if there was only one D18 front output location, it has the same vertical distance between the yoke and the linkage as all the D18's above it. The only possibility here is the exhaust, but as you can see it does not even reach the yoke. Shaft diameter would be the issue here.


    People have said "crawl under a Jeep". I think you guys should try it yourselves sometime and see if you can actually document where an interference would take place if a 1310 yoke was present. I don't think you're going to be able to do it.
     
  15. Oct 29, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    The clearance issue isn't with the bell area, it's along the edge of the pan, right where the yoke area is. That's why the some of the Commando's had a two piece front shaft with a carrier, then went to the smaller joints.AFAIK
     
  16. Oct 30, 2009
    DanStew

    DanStew Incorrigible. Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    Like was stated earlier. THe smaller joints were a result of the commando using the TH400 auto tranny, they needed clearance. With manual trannied vehicles they still used them as carryovers, but the space is there to run larger shafts. IT is agreeable with Jeeps history of maknig do with what they had, they used the smaller yoke and ujoints if they had them. Not to mention over the years the axles and trannys and transmissions could have been swapped in. Bottom line to it all there was smaller unjoints available and were used.
     
  17. Oct 30, 2009
    nickmil

    nickmil In mothballs. Sponsor

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    Something that hasn't been mentioned here is that the smaller yoke also allows the use of a smaller slip yoke, smaller diameter splines, and therefore a smaller diameter tube as well. One thing affects another so to speak.
     
  18. Oct 30, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    We'd have to get some pics of commando with a TH400 to see why they were used.
     
    Last edited: Oct 30, 2009
  19. Oct 30, 2009
    PavementPounder

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    Re: 1966 CJ-5 front driveshaft

    I agree. Those were the next pictures I was chasing in the reply I was composing since FSJ's also used the TH400 D20 with 1310 yokes and didn't clearance issue to the trans.

    [​IMG]
     
  20. Oct 30, 2009
    Patrick

    Patrick Super Moderator Staff Member Sponsor

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    Re: 1966 CJ-5 front driveshaft

    Without the front shaft being connected to the front diff, in the vehicle, we can't see where it might interfere.
     

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