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D18 Speed Gear Removal

Discussion in 'Early CJ5 and CJ6 Tech' started by FinoCJ, Oct 24, 2019.

  1. Oct 24, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,593
    Is it possible to remove/replace a D18 speedo gear without removing or digging into the D18 too far. I probably should have addressed the speedo gear back when I rebuilt, but I didn't, and I seem to remember that it required access inside the case? I could be completely wrong...I am working on restoring my speedo cluster (it starting making horrific noises in moab and the needle broke off) and replacing the cable etc...figured the proper gear for the large tires etc would be nice as well.
     
  2. Oct 24, 2019
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
    Joined:
    Mar 4, 2003
    Messages:
    5,466
    I 'believe' so. I know I put a pulse unit in for my new speedo without pulling the Tcase several years ago when I put it in. Clearance was a bit of an issue if memory serves.
     
  3. Oct 24, 2019
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,513
    Driven gear..yes. Remove cable, unscrew cable adapter. Remove driven gear.
    You might need a thin wall socket (or grind down wall of socket) to fit over adapter.
    Drive gear requires removing the rear output cap.
     
    FinoCJ likes this.
  4. Oct 24, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,593
    This would be the 'drive' gear that rides on the output shaft and thus requires removal of the rear cap (and all the shims etc). (this is stock photo from internet - not mine specifically).
    [​IMG]

    for speedometer correction due to change in r&p gearing or tire size....I should be able to replace the 'driven' gear from the outside through the cable access point...removing the cable sleeve adapter first? These pieces:
    [​IMG]
    I couldn't remember if the cable sleeve that is threaded into the case could be removed from the outside....that might be all I need.
     
    Last edited: Oct 24, 2019
  5. Oct 24, 2019
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
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    5,593
    Also found this from jpflat in another post:
    I authored an article here many moons ago that showed the conversion in part numbers from Jeep to Stewart-Warner.
    You can't go nilly-willy on this; the driven gears have to be matched by series to the drive gear.
    As already mentioned, you need to pull your existing driven gear and count the teeth and record the SW number on that gear and go from there.
    One tooth was usually good for 6-7 mph difference.


    And from Donny:
    There are a variety of speedo gear combinations. The most common are listed below, from parts catalog W 1195 R1:
    4:27 axle 6 tooth drive gear #910086, 18 tooth driven gear #910087
    4:27 axle 6 tooth drive gear #910086( assumed) 20 tooth driven gear #910088 for use with 6.70-15 tire
    5:38 axle 4 tooth drive gear #A-1511, 15 tooth driven gear #A-5707
    5:38 axle 6 tooth drive gear #910086, 22 tooth driven gear #910089


    Nothing specific for 4.88s listed there, and I will have to dig up my pictures from rebuild, but I think I have the standard 6 tooth 910086 drive gear. Since I am running taller tires than oem with 4.88s, figure I could swap in the driven gear for 4.27s to compensate, but which one? the 20 tooth or the 18 tooth?
     
  6. Oct 24, 2019
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
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    8,513
    My experience as stated above was 1 tooth good for 6-7 MPH.
    You may just have to experiment to get what's closest to actual speed.
     
  7. Oct 24, 2019
    melvinm

    melvinm Member

    Arvada Co. 80003
    Joined:
    Aug 11, 2012
    Messages:
    196
    I have several if You need one .
     
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