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Dana 25 VS: 27

Discussion in 'Early CJ5 and CJ6 Tech' started by msbweiland, Dec 28, 2004.

  1. Dec 28, 2004
    msbweiland

    msbweiland Member

    Yakima, WA
    Joined:
    Oct 26, 2002
    Messages:
    80
    Anyone know the exact differances between the Dana 25 & 27? I am pretty sure the 25 is supposed to be stronger because of the larger ring and pinion.
    The reason I'm asking is I was given a Dana 25 with 5:38's and a Dana 44 (10 spline) with 5:38's. I am planning on swapping the rear gears into my current 44 and switching the side gears to the 19 splines. I just can't remember which is the stronger of the two. In a perfect world I'd toss a Dana 30 into the front and call it done, but I can't find one for under $500 within a couple of hundred miles.
    Maybe I'll just wait untill the Puyallup swap meet this spring. What do you think?
     
  2. Dec 28, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
    Joined:
    Sep 22, 2002
    Messages:
    513
  3. Dec 28, 2004
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
    Joined:
    Sep 20, 2002
    Messages:
    6,193
  4. Dec 28, 2004
    linckeil

    linckeil Member

    Danbury CT
    Joined:
    Aug 19, 2004
    Messages:
    492
    The 25 has a larger diameter ring gear, but the thickness is less that the 27. Judging by the looks of the 2 gears, I would say the 27 has the strength advantage. The topic of 8 or 10 bolts on a 27 ring gear has come up a lot lately. The 27 I took apart had 8 bolts. Others have noted discoveries of 8 bolts on their 27 ring gears aswell. All 25's had 8, but some 27's definitely had 8 also. Other 27's may have 10, but I've never seen one. Obviously 10 bolts would be an advantage over 8.
     
  5. Dec 28, 2004
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
    Joined:
    Sep 22, 2002
    Messages:
    5,349
    The center chunk itself is heavier as far as the casting goes, it is wider and has more iron in it. I actually have both gear sets now for a 27, my original dana 27 had 8 bolts and now I find that the dana 27 that is in my jeep now actually has 10 bolts. The knuckles on the later model axles which may include some dana 25's are heavier cast as well than the earlier dana 25's.
     
  6. Dec 28, 2004
    msbweiland

    msbweiland Member

    Yakima, WA
    Joined:
    Oct 26, 2002
    Messages:
    80
    I guess I'm asking whether or not it'll make much differance between the 25 & 27? I have a FI 225, SM465, Dana 18, D44 W/Warn FF kit, D27. 3:73 gears.
    Since I got them for free and I don't do a lot of freeway driving I want the extra low of the differant gears rather than a larger motor. I was wanting to know if I was going to run into a major differance in axles? I ran a welded 25 in the front of a flat fender (33" swampers baby!) for a couple of years with a 350 and never ran into any problems except for the time I jumped it and tore a spindle out of the housing.
    What parts will interchange between the two?
     
  7. Dec 28, 2004
    linckeil

    linckeil Member

    Danbury CT
    Joined:
    Aug 19, 2004
    Messages:
    492
    pretty much all parts interchange without modification except for the carrier. Go with the lower ratio 25 if your running 33's. just be sure the 25 has the late 25/27 style Cardan-Cross axle shafts as outlined in the links posted above by boyink. Anything bigger than 33's and you should swap out to a dana 44 front end (a dana 30 at least). The bigger the tires, the harder it is on the axle. I would say there is not a huge overall strength difference between a 25 and a 27.
     
  8. Dec 29, 2004
    Jeepenstein

    Jeepenstein Me like Jeep..

    North Central FL
    Joined:
    Jun 15, 2003
    Messages:
    2,132
    There is a decent article on this in the newest JP...




    BUBBA
     
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