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27 and 30 yolks

Discussion in 'Early CJ5 and CJ6 Tech' started by ljspop, Oct 26, 2004.

  1. Oct 26, 2004
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
    Messages:
    394
    Any chance I can use the yolk outta my D27 in the D30? Just wonderin' Otherwise I getta figgure out a new driveshaft. I'm kinda worried about it because the small front driveshaft ('68 V6 CJ Donor) would kiss the starter on full flex - I'm afraid a bigger one is gonna compound the problem. I will have more travel though, so I can just go to lower bumpstops.

    Thanks for any words of wisdom.
     
  2. Oct 26, 2004
    schardein

    schardein Low Range Therapy

    Success, MO
    Joined:
    Aug 11, 2003
    Messages:
    553
    I went thru this when I had a dana 27 yoke with the tiny u joint. The yoke was shot for various reasons. Wanted to use my dana 30 yoke and go to a standard size u joint. The splines were the same but the length was not. The dana 30 was shorter as I recall. I could have cut off the bottom portion of the bad dana 27 yoke (the end with the splines) and used it as a spacer, but seemed like the place where they would have met up was right where the yoke seal would have been, which I am sure would not have worked. Going to a 27 yoke on a 30 may work, I can't visualize it now, there were several variables, length of the seal area, length of the splines, length from the u joint cap mounting surface to the surface where the pinion nut seated at.
    Sorry can't give you a straight answer, I ended up finding a good 27 yoke and just having a driveshaft made up brand new(the old one was shot like the yoke, and used a big u joint up front, someone had ground out the centering "lugs" on the yoke and bolted in the bigger u joint with the caps sticking out the sides, just eyeball it to get it centered. Whew, gotta love those previous owners). Used the skinny tube (1"?) just for that starter clearance you mentioned. Its kinda expensive, but you could always do that.
     
  3. Oct 26, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
    Joined:
    Sep 22, 2002
    Messages:
    513
    I seem to remember asking this ? when I did my 30 swap. I ended up buying the right one from Jim, because I was running the D25 before. I bought a used later model driveshaft (CJ7 IIRC) off of ebay for like $10. It takes the wider u-joints, (2 1/2" wide IIRC) but maintains a small diameter tube. Of course if clearance is an issue for you Bob, you could always go spring over. :twisted:
     
  4. Oct 26, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
    Joined:
    Sep 22, 2002
    Messages:
    513
  5. Oct 26, 2004
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
    Messages:
    394
    Hey Johny - someones gotta stay upright to roll you back over :twisted:

    Thanks for the info - looks like I'll have to get a new driveshaft.
     
  6. Oct 26, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
    Joined:
    Sep 22, 2002
    Messages:
    513
    Bob,

    Driveshafts are cheap on ebay. I just shortened the one I got, but you might get lucky and find one the right size.
     
  7. Oct 26, 2004
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
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    394
    I could get an ebay-er but then I'd need a new yolk on the x-fer. Otherwise it seems I'll have to get one made with a small yolk on the x-fer side and a biggie for the axle. I'm confused by the "have it mated to a drive shaft that fits the Dana 30" bit above. Lop the axle end little yolk off and have a big yolk welded in it's place? Are the tube diameters the same?
     
  8. Oct 26, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
    Joined:
    Sep 22, 2002
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    513
    I was confused by that part too. I was looking more at what nickmil wrote. Yes the tube on the new shaft was the same as my old one, but i'm not sure it's the same diameter you are running. IIRC it was like 2" tube size, or maybe 1 3/4. I know some of the D shafts look so small that they actually look like a solid bar. I switched to the large yoke on the transfer case, so both ends of the shaft have the same U-joint. I got the large yoke for the xfer from someone here on the forum.

    I'll look to see what I have around here you might be able to use. (my old broken front shaft).
     
  9. Oct 26, 2004
    Alex

    Alex New Member

    Frederick, MD
    Joined:
    Aug 3, 2004
    Messages:
    21
    "Of course if clearance is an issue for you Bob, you could always go spring over." Originaly Jonnie Jeep
    Not any more! Eh Bob?
     
  10. Oct 26, 2004
    AKCJ

    AKCJ Active Member

    Fairbanks, Alaska
    Joined:
    Aug 12, 2003
    Messages:
    1,033
    My front drive shaft rubbed on the bottom of the starter before I put on the 2.5" lift springs. The old original springs were really sagging. I wouldn't think it would rub if the springs weren't sagging? Just a thought.

    The small yoke on the front of the t-case may be the weakest link in my entire drive train. I have always thought about replacing it if I could ever find a larger one. Or at least find a spare (small yoke) to carry on the trail.
     
  11. Oct 26, 2004
    ljspop

    ljspop Lurking Bronco Dude

    San Diego, CA
    Joined:
    Jan 29, 2003
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    394
    Mine only rubbed on full stuff. I guess that'll be further away with the new springs. I'll know soon enough :D
     
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