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rear end gear questions

Discussion in 'Intermediate CJ-5/6/7/8' started by earlswrench, Jun 1, 2013.

  1. Jun 1, 2013
    earlswrench

    earlswrench Member

    Atlanta, GA
    Joined:
    Apr 14, 2009
    Messages:
    135
    I'm going to bigger tires (33s probably) from the stock size on there now. So, I want to go up in gears to 4.10 or 4.56

    Currently, I'm running 3.07 on '78 International Scout Dana 44 axles. (well...."running" isn't exactly true. I haven't got the body back on the frame since the axle swap.....)

    I have heard that on some Jeep Dana 30s, the smaller carrier will take some bigger gears, even though the larger carrier is supposed to be used for the bigger gears.

    If I go up to 4.10 or 4.56 on a Dana 44, do I HAVE to change out the carrier too?

    Also, if I do need to change the carrier, does that mean I need new spider gears, etc. or will those swap from my current carrier to the bigger one?

    Thanks.
     
  2. Jun 1, 2013
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,529
    The differential CASE is the part the ring gear bolts to and houses the differential gears (pinion and side gears). This part is NOT a carrier.

    On a Dana 44 the gear break for the case is 3.92-5.38 ring and pinion sets (4 series) and 3.73-2,54 gear sets (3 series).
    The 3 series case can be used with 4 series gears if a ring gear spacer is used (I highly recommend against this) or if a gear set with an extra thick ring gear is used. These are typically aftermarket gears and have to be purchased new unless you are very fortunate.
    You cannot use 3 series gears on a 4 series case at all.
    The case can be different also depending on spline count of axles used. 10 and 19 spline cases interchange and 27 and 30 spline cases interchange. In other words you cannot put 30 spline side gears in a 19 or 10 spline case.
    So, if you want to run say 4.10:1 ring and pinion, you would either need a gear set with an extra thick ring gear to use your 3 series case, or you will need a 4 series case meant for your axle spline count (should be 30 spline if flanged axle).

    I don't know what you mean by "larger" or "smaller" gears as Dana 44's use the same diameter ring gear regardless of gear ratio and so do almost all axles.
    I also don't know what you mean by larger or smaller "carrier" (I assume you mean the case) because Dana 44 cases are dimensionally the same with the exception of the bearing journals, the inside diameter of the case where the side gears fit, and the location of the flange where the ring gear bolts.

    Sent from my iPhone
     
    Last edited: Jun 1, 2013
  3. Jun 1, 2013
    earlswrench

    earlswrench Member

    Atlanta, GA
    Joined:
    Apr 14, 2009
    Messages:
    135
    Thanks Nic, you answered my question perfectly.

    Regarding case vs. carrier, sorry about not being too specific. I've been working from a lot of researched sites on gear set up and some call it the case and some call it the carrier. Even this very good write up http://www.pirate4x4.com/tech/billavista/Gear_Setup/ points out that, although the technical term is case, so many people call it the carrier that the names have become synonymous.

    Also, when I was talking about the bigger gears and bigger carrier, I was -- very poorly -- referring to the ratio numbers, not specifically the size of the object. I willingly take my lashes on that one ....
     
  4. Jun 1, 2013
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,529
    I understand and I'm trying to educate my little corner of the world. This commonly misused language leads to mistakes and confusion. For example, if I order a carrier for a Ford 9" axle what part should I receive, the case or the carrier?


    Sent from my iPhone
     
  5. Jun 3, 2013
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
    Messages:
    2,115
    On a dana 44 you can use a jeep rubicon tick gear 4.10 they are made for the 3.03-3.73 case.

    Also what transmission you have? i do have the t-18 with the dana 20 combo on scout dana 44. It work perfectly for me, i have a good crawl ratio and a good ratio on second for mud application. I might consider a t-case gear swap to get a wider choice of ratio.
     
  6. Jun 4, 2013
    jdarg

    jdarg Member

    SE Wisconsin
    Joined:
    Jan 27, 2010
    Messages:
    92
    Actually you aren't limited to the stock Rubicon 4.10's either. You can get 4.56 and 4.88 D44 thick gears as well. The aftermarket started making them ~ 2003 when the Rubicons came out IIRC so people wouldn't have to ditch their factory air locker setup if they regeared. They should be easy to find.
     
  7. Jun 4, 2013
    earlswrench

    earlswrench Member

    Atlanta, GA
    Joined:
    Apr 14, 2009
    Messages:
    135
    Upon further research, I have discovered that '93 to '97 Isuzu Rodeos used thick 4.10 and 4.30 D44 gears that cross reference with Scouts.

    At my local Pull-a-Part, I found three Rodeos in that range of years with 4.10 gears and two more Rodeos with the 4.30 gears. From what I can tell, the front Rodeo gears are different but on my Scout axles, the rear gears and front gears are the same (unless I am completely wrong, please let me know if I am). So, I should be able to pull two sets of rear gears from two Rodeos and use them -- a lot cheaper than buying new. Only visual inspection will tell the condition, but absent a rear end wreck or serious abuse, I'm guessing they would look pretty good.

    From what I understand, the only difference is that the Rodeo uses a crush sleeve and the Rodeo pinion uses a different bearing size (of course I was going to buy new bearings anyway).

    Anyone have any experience/opinions with this?
     
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