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5.13's?

Discussion in 'Early CJ5 and CJ6 Tech' started by Southtowns27, Sep 2, 2004.

  1. Sep 2, 2004
    Southtowns27

    Southtowns27 Custom Title

    The Backhills of...
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    Are/were 5.13 gears available for a 44 and a 27? I'm still crunching numbers about what ratio would be best for me and this is what I came up with. 4.88 is a little too tall and 5.38 is a little too short. I'll get this all figured out one of these days........
     
    Southtowns27, Sep 2, 2004
    #1
  2. Sep 2, 2004
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
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    5.38 and add an OD?
     
    Boyink, Sep 2, 2004
    #2
  3. Sep 2, 2004
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    timgr, Sep 2, 2004
    #3
  4. Sep 2, 2004
    James P. Enderwies

    James P. Enderwies Sponsor

    Lake Havasu City, AZ
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    You know, funny you should mention 5.13's. The last time I talked to the PO of my '68 I ask him what gears he had in it. He put a Detroit in the rear and a Lockright in the front so I know he had been thru them. He said "...something like 5.13 or so". I had never heard of that ratio, so I said "...you mean 5.38's?". He said "..yea that must be it".

    I've never got around to jacking up the front and turning the DS and counting tire revolutions, but the diff. between 5.13 and 5.38 would be readily apparent.

    I just "may" have 5.13's in the 44 & 27. :shock:
     
    James P. Enderwies, Sep 2, 2004
    #4
  5. Sep 2, 2004
    Southtowns27

    Southtowns27 Custom Title

    The Backhills of...
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    I have an OD now, just put it in last week. Here's the problem: I have 3:73's now. With the OD engaged, that raises my final drive ratio to 2.79...with 31" tires it doesn't work out so good. I'm planning on switching to 33" or 34"s in the near future, so that would make the situation even worse. 4.88's with the OD gives me a final drive ratio of 3.66. Slightly higher than I have now, but with larger tires I again, lose more RPM. 5.38's with the OD gives me a final drive ratio of 4.04. Even with the bigger tires it's still shorter than what I've got now. 5.13's work out almost perfect. With the OD and bigger tires it would knock about 250 rpm off my highway cruise rpm.
    The safe answer is 5.38's...I'll never run out of power, but I don't want to kill my mileage. 4.88's MIGHT work, but I don't want to put them in to have the thing be a slug....
     
    Southtowns27, Sep 2, 2004
    #5
  6. Sep 2, 2004
    JohnyJeep

    JohnyJeep BLOWING A XING NEAR U@2AM

    Beautiful Cody WY
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    Well you also have to figure that tires run about 1/2" to 3/4" shorter than advertised as well. I am going to run 34's with 5:38's and the O.D. I was running worn out 31's before and it would tach about 3200 RPM at freeway speed (70). I'm hoping with the same gearing and 34's my RPM will drop to 2800 or so. We'll see.
     
    JohnyJeep, Sep 2, 2004
    #6
  7. Sep 2, 2004
    scottbruns

    scottbruns New Member

    Phoenix, AZ
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    Consider 5.38s. Even though 5.13s look good on paper, you might wish you had the extra low gearing to overcome the extra mass of those larger tires and rims.

    Gas mileage, what's that?
     
    scottbruns, Sep 2, 2004
    #7
  8. Sep 2, 2004
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
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    That and 5.38's are the Dutch Deal - much more plentiful since they were common on the 4 cyl. Jeeps.

    In fact, SSDutch has them, and I'm going back to the 4.27's that Dutch had. With the V6 and 32's it still had plenty of power - even back when I had the OD.
     
    Boyink, Sep 2, 2004
    #8
  9. Sep 3, 2004
    66cj5

    66cj5 Jeep with no name

    NorthWest Indiana
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    32's and the 4.27 gears equal out to 3.8 or so gearing.
     
    66cj5, Sep 3, 2004
    #9
  10. Sep 3, 2004
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    I think you are splitting hairs here, between 5.13 and 5.38:1. Yes, there IS a difference, but it is almost negligible.

    I say this because I debated back and forth between swapping my Dodge Dakota's 3.55 gears out for either the factory optional 3.92 or aftermarket 4.10 gears. Why? the factory tow ratings increased by 1000# by doing it. I went with the 4.10, to gain that little additional torque multiplication. Mileage actually IMPROVED around town, but it dropped about 2 MPG at 70 MPH.

    IMHO, if you are that worried about gas mileage, buy a Hyundai!

    Your mileage may vary! ;)
     
    w3srl, Sep 3, 2004
    #10
  11. Sep 3, 2004
    Boyink

    Boyink Super Moderator Staff Member

    Tulsa, OK
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    Yeah, but they're not really 32".
     
    Boyink, Sep 3, 2004
    #11
  12. Sep 4, 2004
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    :shock: Unless your 283 is a dog, then 4.88s would be excellent. 5.38s would give a little better crawl ratio of course.
     
    Glenn, Sep 4, 2004
    #12
  13. Sep 8, 2004
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    5.13's are not available for a 27. You'd have to switch to a dana 30 for that. Nickmil.
     
    nickmil, Sep 8, 2004
    #13
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