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Changing 3.21 to 3.73

Discussion in 'Wrangler JK (2007-2017)' started by wkryssing, Jun 24, 2017.

  1. Jun 24, 2017 at 1:52 PM
    #1
    wkryssing

    wkryssing [OP] Member

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    2014 Jeep Wrangler Sport 3.21 gears
    None - but I want too.
    whats the cost to change from 3.21 to 3.73 gears and what else do I need to do? so I can tow my boat...
     
  2. Jun 24, 2017 at 2:31 PM
    #2
    SmittyJeeper

    SmittyJeeper Well-Known Member

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    5" lift, 4.11 gears, tru-trac limited-slips, winch, bumbers... you know the rest.
    You can find gear sets for around 500-600 bucks online complete with gears, bearings and seals but in most cases if you have stock gears numerically lower than 3.73 you will need to change the carrier as well. It's around $1,000 in labor to do both axles and carries are a few hundred alone. I would go 4.11 if you are towing the v6 engines in newer jeeps don't have much torque on the low end.
     
  3. Jun 24, 2017 at 2:39 PM
    #3
    aggrex

    aggrex Well-Known Member

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    Ya what Smitty said! Since you will be spending some $$ labor to install gears this may be the time to consider lockers and maybe 4.88s with your future 37s
     
    HardHat420 likes this.
  4. Jun 24, 2017 at 5:15 PM
    #4
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    i bet you could find 3.73 or 4.10 axles on ebay or craigslist for under 1800 from somebody upgrading to bigger axles. then sell yours to recover some of the expense.
     
  5. Jun 24, 2017 at 5:27 PM
    #5
    aggrex

    aggrex Well-Known Member

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    Not sure there be many takers on the 3.21 gear sets unless the next gas crunch resurfaces again
     
  6. Jun 24, 2017 at 6:26 PM
    #6
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    According to Revelution Gear and axle (owned by the engineers of the shut down Superior gear and axle) You only need a front carrier. So the rear locker is a recommendation, but not needed.

    this is what it would cost you for parts:

    Rear Detroit locker $620*
    Front Detroit True track limited slip differential (I would get a full selectable locker) $510+
    OR
    Front Eaton E-locker (electric) $830*
    Revelution Gear Front & Rear ring and pinion and install kits 4.11,4.56,4.88,or5.13 $495+*
    Estimated labor cost $1600+*
    ___________________________________________________________________________

    +Bare minimum for installation $2605
    *Recommended for installation $3545

    ___________________________________________________________________________
    ___________________________________________________________________________

    Either way you go the labor is the same because you will have to break down the axles completely to install the new gears. You might be able to save $100-200 if you shop around on the internet for the parts. Order out of state to save tax. I know of a guy here who will do the labor for $600 an axle. That would save you another $400 so shop around. I do my own axles because working on my jeeps is my stress relief and I really enjoy the work.

    Have fun with the project.
     
    aggrex likes this.
  7. Jun 24, 2017 at 6:44 PM
    #7
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    I just found that you can order an empty carrier for the Front Dana30 for 3.73 gears and up for $80 from Revelution gear. You will have to switch over your spider gears from your current carrier. If you are on a budget that will save you $430. You are now down to $2200 for the whole project.
     
  8. Aug 5, 2018 at 5:30 AM
    #8
    JoeInOh

    JoeInOh Active Member

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    I kind of fell into the JKU I bought. I had been looking at different models and numbers, order packages, the JK vs JL, etc - that when I found this 2017 JKU leftover model at a great price - the one thing I missed/overlooked was the 3.21 gears it had. I was definitely disappointed when I realized it a few days later as I was planning to order a JLU with the tow package. Stupid!

    So to see these regearing prices you guys are throwing - it's not going to happen.

    Although my whitey is a bit gutless, I am averaging 20.8 mpg in mixed driving in its first 2600 miles. I'm happy/surprised about that.
     
  9. Aug 5, 2018 at 6:27 AM
    #9
    aggrex

    aggrex Well-Known Member

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    I feel your pain....regearing will be one of the top jeep expenses for many of us so start saving ;) Add in lockers, gears, axle shafts and the bill creeps higher.
     
    JoeInOh likes this.
  10. Aug 5, 2018 at 9:40 AM
    #10
    RubiconFreedom

    RubiconFreedom Seven Jeeps in Forty Years

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    After special ordering a 2017 unlimited with the 3.73, we're unable to notice any difference in th gearing as well as the fuel economy. But we've yet to install the hitch and tow anything. But it is what we wanted as compared to the 3.21.
     
    JoeInOh likes this.
  11. Aug 8, 2018 at 7:19 PM
    #11
    Squatchy

    Squatchy Well-Known Member

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    If you change the gears in a newer jeep you have to order a recalibrator or programmer. The jeep will go into limp mode if you do not recalibrate the computer to match the gears you put in it. I learned that the hard way. I did the front and rear gears in my 2017 for under 1000. That’s not including the lockers. If you have never done it before I would recommend having a shop do it. If you don’t get the shims right then your gears won’t last long.
     
    aggrex and JKBob 25 like this.
  12. Aug 9, 2018 at 11:45 AM
    #12
    Awrench

    Awrench Well-Known Member

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    for debate or thinking - always fun spending OPM,
    did you check 2014 wrangler tow rating- not hauling a whole lot of beer. What your dingy weight?

    What tires NOW - 225/75/16 , 255/75/17, 255/70/18, 255/75/17 . use 31" to do math est.
    get smaller tire for towing...
     

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