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Thread: TJ Sahara Gear ratio

  1. #1

    Question TJ Sahara Gear ratio

    I have a 98 TJ Sahara and it did have the 30" tire package. What is the stock gear ratio? It's either 3.73 or 3.07. I wish it was 4.56

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    Brad
    98 TJ Sahara
    Brad
    98 TJ Sahara

  2. #2
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    If you want to know 100% what ratio you have, do this:

    On a level surface, block the front tires & take the trans out of gear (this works for auto or manual trans). Jack slightly up one rear tire if you have an open diff, or both tires if you have a working posi or locking differential. Rotate the rear tire one full revolution for posis and lockers and 2 full revolutions for open diffs. At the same time, carefully count the number of full evolutions the driveshaft makes. This is your differential gear ratio. In other words, if the drive shaft turns 3 ¾ turns (if you run locked & only spin the tire once), you probably have a 3.73 gear ratio. Turning the tire for twice the original number of full revolutions and dividing the drive shaft revolutions by two will give you a more accurate reading.

    This entire process takes me ~1 minute with a couple blocks of wood in my garage & a floor jack.

  3. #3

    Post

    Thanks for the suggestion!

    ------------------
    Brad
    98 TJ Sahara
    Brad
    98 TJ Sahara

  4. #4
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    I have a 98 TJ Sahara and it has 3.73's.

    HTH
    Phil
    God created alcohol so the Irish wouldn't rule the world.

  5. #5
    Registered josta's Avatar
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    Thumbs up

    Go to www.4lo.com , they have an interactive calculator where you plug in 3 of the following; RPMs, MPH, tire size, and gear ratio, and it will figure out the rest. In your case, you input the MPH, RPMs, and tire size, and it will tell you your gear ratio.

    It's easy; no muss, no fuss!

    I, too, have the 3.07 ratio and 30" tires, and personally, I'm happy with the setup; keeps my RPMs to a comfortable 2500 at 70 mph.

    John

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    1999 Jeep Grand Cherokee Laredo 4x4 , pampered, flame red with matching Bugflector II, DC trailer hitch, garaged, driven only on nice weekends.

    1997 Jeep Wrangler Sahara 4.0L, auto, forest green with tan hardtop, hitch, air, partially debadged, tinted windows, dual position door straps, Bestop bikini, 100w fog lights, Warn X8000i winch, driven rest of the week, rain, snow, or sunshine.



    [This message has been edited by josta (edited 11-18-2001).]
    1997 TJ Sahara 4.0L, "HUMMER RESCUE SQUAD", auto, BONE STOCK (except for D30/ARB, D44 /ARB, 3.73s, 33x12.5 MT/Rs, 15X10 Eagle 058s, RE 4.5" LAs, Daystar 1" BL, Currie 1" MM, SYE, CV, Kilby, Tera, and custom skids, Poison Spyder armor, Currie TJ Steering System and trac-bar, Rock-it guards, Hella H4 100W headlights, 55W backups, 120W PIAA 80s, Rock-Hard roll cage, built-in 120 volt inverter, Garmin GPS182C, Ravelco anti-theft, Warn front bumper w/ X8000i and 125' MP line, Currie rear bumper/tire carrier, Dual QuickAir2s, Sun air tank, truck air horn, K&N with TurboCity intake, Borla headers, and a bunch of other stuff. License plate: HUMR RSQ .And my 2 sons in my rear view mirror in their growing Jeeps!

  6. #6
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    You know the count the revolutions method works well for large gear discrepancies such as 3.07 to 3.73 or so but gets a littly fuzzy between 3.55 to 3.73.

    No one talks about it but there have to be codes on the gear rings themselves and if it is time to change the fluid and inspect then is the time to get them.

    Just my nickel (was $0.02 darn inflation )

    - 2006 Liberty Sport CRD "Smogger", Dark Khaki, stock and staying that way. P.S. I am slowly getting addicted to SIRIUS.............

    - 82 CJ-8 Light Khaki metallic restored. 4.0L engine and fuel injection rebuilt and ready for transplant.

    -99 TJ "sport" 4.0L auto sold to my father, oh well I can still borrow it.

    -93 YJ (RIP 9/6/04) oh well the 4.0L 32RH will nicely replace the CJ8s 4.2L TF999.

  7. #7
    www.stu-offroad.com Stu Olson's Avatar
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    <font face="Verdana, Arial" size="2">Originally posted by Jimbob:
    You know the count the revolutions method works well for large gear discrepancies such as 3.07 to 3.73 or so but gets a littly fuzzy between 3.55 to 3.73.

    </font>
    To the best of my knowledge, '98 TJs were not offered with 3.55 gears. 3.73s would be normal for a manual tranny for a '98. (Of course, someone could have put different gears in too which makes the above N/A.


    ------------------
    Stu's '98TJ Sahara
    Detroit Locked & Loaded
    www.stu-offroad.com
    Stu's '98TJ Sahara
    ARB Locked & Loaded
    www.stu-offroad.com

  8. #8
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    Ya stu, as you know I dont know TJs well and whether they used 3.55s at all but they pop up frequently in YJs.
    Just my nickel (was $0.02 darn inflation )

    - 2006 Liberty Sport CRD "Smogger", Dark Khaki, stock and staying that way. P.S. I am slowly getting addicted to SIRIUS.............

    - 82 CJ-8 Light Khaki metallic restored. 4.0L engine and fuel injection rebuilt and ready for transplant.

    -99 TJ "sport" 4.0L auto sold to my father, oh well I can still borrow it.

    -93 YJ (RIP 9/6/04) oh well the 4.0L 32RH will nicely replace the CJ8s 4.2L TF999.

  9. #9
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    <font face="Verdana, Arial" size="2">Originally posted by PHIL98TJ:
    I have a 98 TJ Sahara and it has 3.73's.

    HTH
    Phil
    </font>
    Sorry, I forgot to mention I have an auto tranny.
    God created alcohol so the Irish wouldn't rule the world.

  10. #10
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    FOrmy sahara i have 3.73, bu to make sure just check on the differential cover, there will be a piece of metal that tells you.
    99 sahara 4" Pro Comp lift, 33x12.5 BFG MT's, Tomken rear bumper and tire carrier, teraflex qd's. Waiting to win the lottery........(sold)

    02 F250 XLT 4x4 with DR Leveling Kit and 315's

  11. #11
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    Give the VIN to a dealer. Assuming your gears are stock, the dealer will run a report showing the factory installed options and specs, including gear ratios.
    1995 Ford taurus Station Wagon
    100% stock
    Third seat option

  12. #12

    Post

    Yup, there is a piece of metal on the diff. cover that has the stock gear ratio 3.07 on there.

    Had to buy a new carrier, damn!

    ------------------
    Brad
    98 TJ Sahara
    Brad
    98 TJ Sahara

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