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Jeep T18 Into Cj6

Discussion in 'Intermediate CJ-5 and CJ-6 Tech' started by IrishCJ6, May 7, 2018.

  1. May 7, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
    Joined:
    Dec 6, 2010
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    398
    Following on from my earlier post about a clutch release bearing.

    Today we pulled the T18 from the J20 truck, 40 years of crud made working underneath it a pain in the backside but eventually it came free.

    IMG_20180507_52782.jpg

    IMG_20180507_10764.jpg

    IMG_20180507_56860.jpg

    IMG_20180507_38553.jpg

    IMG_20180507_20690.jpg

    IMG_20180507_23607.jpg

    It is a T18 with granny first, it has the standard bellhousing, a cast 1" spacer between it and the trans and another cast 1" spacer between the trans and the D20. It had a few signs that bits of it had been apart before, PTO plate had been off and the D20 had been off at some stage as well. The D20 has a longer shifter mech than the CJ but uses standard parts so should easily be adapted to suit the CJ6.

    All looked good until we gave the input shaft a spin, unfortunately there was a hum and a wobble indicating at least a worn front bearing. So we washed it and decided to split it and open the T18.

    Opening up the top cover revealed the reason for the bearing failure, looks like the PO didn't know how to shift with a non syncro setup and there was some tooth damage on first/reverse and idler gears. This obviously toasted the front/rear bearings.

    IMG_20180507_33129.jpg

    IMG_20180507_40882.jpg

    The question is what to do next. I'm living in Ireland and don't have the parts handy to rebuild, I can buy same and ship but I assume costs could be high. Thoughts were that damage isn't too bad and live with it and just replace bearings etc.

    Would be keen to know your thoughts on same and where is best to source new parts at reasonable costs.

    On the plus side the D20 looks perfect and has probably been rebuilt at some stage.
     
  2. May 7, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Woohoo. It's a Jeep.

    JMO - the rounded gears likely are not the reason for main bearings failure

    I'd run it considering your location. Parts Mike has the gears if you decide to replace them. The main bearings must come off to get into a T-18. If you are going to replace bearings, see my thread here - T-18 in the driveway - Full Size Jeep Network

    You should take it apart and evaluate the front main bearing and the pocket bearing between the input shaft and the main shaft.
     
    Last edited: May 7, 2018
  3. May 7, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
    Joined:
    Dec 6, 2010
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    398
    Timgr,

    There are some marks on the largest gear (1st/reverse i suspect) and then the idler gears underneath (all straight cut gears), one tooth on the large gear has a chip. There is a little pitting on 3rd gear. All syncros are in very good condition.

    The question is, can I get away with giving this a clean up, replace the bearings and just run it as is, or do I need to replace the gears that have chips/wear which will be come expensive.

    I want the opinion from those that has seen this sort of stuff before as I don't want to open a can of worms.
     
  4. May 7, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    Dec 6, 2010
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    398
    Correct gear names that have wear/damage and I need opinions on

    2nd Synchronizer Assembly
    Reverse Idler Gear Assembly
    Countershaft Gear
     
  5. May 7, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    T18-12 1ST AND REVERSE GEAR

    I had some chips and rounding on that gear in my T-18, and I put it back together with the old gear in place. IMO it's likely to be ok. I would look at the bearings, including the pocket bearing in the main shaft, before I decided much. That transmission is very strong for a CJ, and I expect that it will be fine. However, I would look at all the gear teeth for big chips and make my decision based on the worst cases. All these transmissions have some rounding of the corners on those gears, but if you see big chips missing, that is worse.
     
  6. May 7, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    Dec 6, 2010
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    398
    There is only 1 chip in the second gear synchroniser it's only a partial chip, the rest are only wearing marks where someone has changed gear without stopping first or timing the change. My friend who's a very experienced mechanic thought it was too bad and should be fine also.

    Looks like a just need a rebuild kit now, any opinions on who to go to for same?

    On another point the shifter on the transfer is completely different to the CJ style but I sort of like it as it would seem like a much better/stronger setup. Has anyone modified one of these to suit a CJ before or could give me some pointers of why they were different
     
  7. May 7, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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  8. May 7, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Can't comment on your kit - don't know anything about the seller. I've bought all my T-18 parts through Parts Mike.

    5358285 is the real deal; 1979 10/20/40 with a 258.
     
  9. May 8, 2018
    fhoehle

    fhoehle Sponsor Sponsor

    Eynon, PA
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    I would recommend rebuilding it, as rebuild kits are reasonable for this transmission. Do the Xcase while it is out as well. You can get away with dressing the edges of the teeth up a bit with a die grinder or get replacements. If there are chips, I'd probably get new gears but it really all up to you and your wallet. For me it's up to me and the financial department (my wife-who is a Scot, and cheap!). It would be easier to do it all now than get it together and do it all later in dribs and drabs.
     
  10. May 8, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    You could read my thread I posted above about my repair. I replaced the main bearings. Originally I bought Timken bearings from RockAuto, and they kept sending me the wrong part for the front main bearing. Eventually they gave up and said they could not help me any more. There is a narrow and wide T-18 front main bearing, and I believe your transmission uses the narrow bearing. I recall I posted the widths in the thread. I could not find any front main bearing except for the Chinese bearing. The rear bearing is available in major brands and Japanese, but the front bearing seems only to be available in a Chinese import. I rejected the first one they sent me, and the replacement was much smoother.
     
  11. May 9, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    So a bit of an update

    ●Input shaft is 19mm (Or very close)
    ●Has a 20mm wide front bearing
    ●Has the modern style selector fork

    So on all accounts it seems to be a mix of the parts bin. Being a 79 it should have a 17mm input shaft, 23mm bearing?

    So I'm a little lost.

    Looks like the counter shaft gears are fine as are the reverse gears (slight file required) so only the 1st gear needs replacing.

    Trying to establish the best rebuild kit to buy and a replacement 1st gear.
     
  12. May 9, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    My '82 has a 20mm wide bearing, so I would expect a '79 to also be 20mm. This is the Chinese bearing (Crown?) that I used. The rear bearing should be 23mm wide, and available from Timken and other name brands.

    You mean the input pilot? Should be easy to pick the proper pilot bushing. Likely you can pick a pilot bushing for any 360/T-18 Wagoneer or J-truck '72 or later and it will be correct.
     
  13. May 9, 2018
    tarry99

    tarry99 Member Sponsor

    Northern California
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    Normally the 1st / Reverse sliding gear damage will also get the counter shaft below.......notwithstanding all the bearings from the trash running through there.....( If you rebuild glue a couple of magnets to the bottom of the case inside) and as mentioned above you can dress the gears with a stone on a die grinder..........the percentage of metal removal on each tooth has been the topic of discussion by many , numerous times before as to how that relates to when is it finally time to replace them?

    That answer may simply lie in how your going to drive and use the vehicle..........no question that it weakens the tooth or teeth , no question that in future gear engagements into 1st & Reverse there is a high probability that chipping may / will continue due to the fact the heat -treat hardening process is only so deep and by grinding it's being removed................and no question that more than likely it may also want to jump out of gear which only means you may have to hold the shifter in that position when maximum torque is being applied in those gears...............

    Nothing will change the damage already created............Run it for a while and see how it works for you....................At the very least if your going to keep the vehicle planning ahead to source the parts for a future rebuild may not be a bad Idea.
     
  14. May 9, 2018
    rejeep

    rejeep Sponsor Sponsor

    Rochester, NY
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    rebuild
     
  15. May 9, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    Anyone got any experience with;

    American Powertrain Warehouse?
     
  16. May 9, 2018
    tarry99

    tarry99 Member Sponsor

    Northern California
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    Never heard of them..........used to be a guy in Las Vegas and a gal in Oklahoma that sold tons of BW T-18 parts........Keep in mind these transmissions are still being used in the well drilling industry in the mid west..........and there prices were cheap as compared to the Jeep parts guys...

    The Gal in Oklahoma:

    BLUMENTHAL HEAVY DUTY


    504 SW 4TH ST

    OKLAHOMA CITY, OK 7310

    had a huge inventory of B&W OEM parts that she was looking to wholesale out pallets of parts.......she was nice enough to sell me some miss. Items I bought a few New T-18 cases , clusters and sliding gears ETC, .....and tried to find some interest from some of the Jeep guys to buy it all , but no takers..........last time I tried to reach her there was no reply............and since I decided to go Auto trans , I sold everything I had to one of the members here..............If I was looking to find that stuff right now I would concentrate my search in and around Texas , Oklahoma & Nebraska at some of the industrial gear house's...........you'll need part #s and that info should still be available on the internet.........Good Luck!
     
  17. May 11, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    Has anyone got any thoughts on a company called Cobra Transmissions? They seem to have all the parts I need and their prices seem good.

    From what I see there is a bearing kit that comes with front/rear bearing and all the small parts plus gaskets. Every place I look seems to sell the same kit (at varying costs) but the kit looks identical. Has anyone got any experience with these rebuild kits and and do/don'ts with using them (ie quality).
     
  18. May 11, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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  19. May 11, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    And are they OK?

    Do you ever sleep?
     
  20. May 11, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    I presume so. If you worry, use one of the vendors with a reputation to protect, like Novak or Parts Mike or even Herm the Overdrive Guy. Call them and ask them about parts quality. I think the Crown parts are a safe bet, except perhaps for the quality of the main bearings. If you'd rather, you can buy the small parts kit and the gasket kit separately, then purchase whatever bearings you prefer. I would probably reuse most small parts - that's what I did for my "rebuild."

    Yes, I do sleep. :sleep:
     

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