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What Axles to Use?

Discussion in 'Early CJ5 and CJ6 Tech' started by linckeil, Nov 1, 2004.

  1. Nov 1, 2004
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    I'd guess yes, since the guts interchange but I'm no Nickmil. :D
     
  2. Nov 2, 2004
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
    Joined:
    Dec 22, 2002
    Messages:
    4,418
    No kidding.

    I was wondering why the extra trans I got was marked t90a and t90c. I just thought it had been rebuilt from parts someone had that were good.
    This is the trans that was infront of the ford transfer case I found.
     
  3. Nov 2, 2004
    steverdenver

    steverdenver Member

    Denver,(Littleton...
    Joined:
    Sep 27, 2002
    Messages:
    61
    Well All,

    My 1966 CJ6 with a 134F head had a standard t90C-- (of course)

    I mated the t90C to a Buick V6 by putting in an older t90a cluster gear and a T90J main input shaft. This was done because the t90c input shaft and cluster gear are different than the earlier t90s. The t90J was run with a straight six engine in Jeep PUs and Stationwagons. The stock t90J can be used to mate with a V6 or V8 with an adapter infront of the T90 because it has the long main input shaft.

    This method of mating another engine (engine Swapping) by modifying a T90 with a T90J input shaft is the olden days way of upgrading an old classic early Jeep.


    For Boynick's edification-- a 1960ish Rambler straight six bolts to a T90 with a 1/2-3/4 inch spacer-- or shortening of the input shaft and directly bolting it to the t90-- and in the 1960s was a popular swap (a realitive statement). And Rambler overdrives were mated to the rear of D 18s often(called the 'Rancho Overdrive'). I owned many a Rambler in the 1970s-- and could buy them for 25 to 100 dollars in running condition.

    Back in the late 1960s and through the 1970s lots of V8 Jeeps were run and raced with T90s--- and worked really well. I had lots of Jeeping friends that ran Chevy 283s and 327s against T90s long with small block Ford V8 engines---If you were reasonably careful the T90 would not break. They are only too high geared and / or weak if you run very large tires (bigger than 31s)--- or if you want to rock crawl.
    Stock driveshafts will usually fail long before a T90 would fail-- and two piece axles usually break first too. Ofcourse with a worn-out T90 that is a different story.
    But they are easy to rebuild-- Just put new bearing, countershafts and a 2nd gear and run them for another 10-20 years.

    You can do very well with a Jeep running a 200- 250 CI engine and a T90-- as long as you are not building a monster.

    The popular transmission conversion through the 1980s was a Ford 4 speed top loader or a Muncie 4 speed car transmission--- for strength and smooth shifting. Only very few sm420 were converted-- because rock crawling was not a popular sport back then. --- And big tires were not so cheep (realitive statement).

    A t90 will deliver slighty better gasoline milage too---less weight , gear resistance.

    ofcourse if you want a extra low geared Jeep do the sm420 thing--- or some other conversion--- if you really want. I got a couple sm420s lying in my garage-- ran one in a Nissan Truck-- they are LOW geared in granny....


    My 2 bits
     
  4. Nov 2, 2004
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    23,596
    Stever, I expect this was the L-head Rambler engine? I didn't think that there were any OHV Rambler 6s prior to the 198.

    I'm wrong about the T90C - Warloch is right. The T90C does have lower gearing, but there's no mainshaft available to increase the stickout so you can use a deeper GM bellhousing (like the V6s and SBCs). The change to the long input from a T90J requires the change to a different cluster gear, effectively changing the T90C into a T90A. Both the T90A and T90C have "T90A" cast into the case - look at the tag or count the teeth on the input gear - IIRC 16 = T90C, 18 = T90A.

    If you want to go with a shallower bellhousing like the Pinto, Studebaker 6, Rambler 6 and maybe the Falcon I6, you can keep the 16 tooth input gear.
     
  5. Nov 2, 2004
    66cj5

    66cj5 Jeep with no name

    NorthWest Indiana
    Joined:
    Sep 10, 2003
    Messages:
    2,084
    what's w/t-14????? :?
     
  6. Nov 2, 2004
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
    Joined:
    Mar 4, 2003
    Messages:
    5,466
    I like the synchro all around in a 14, but they are just not as strong due to those as well. Based on experience, I have had MUCH more luck with a T90 (less rebuilds needed based on usage).

    My son's '46 has one in it, works OK just needs more 'lookin after' than the T90's in all the other jeeps. They have been that way for years - just my opinion.
     
  7. Nov 2, 2004
    linckeil

    linckeil Member

    Danbury CT
    Joined:
    Aug 19, 2004
    Messages:
    492
    Well I just won me an overdrive unit on ebay for cheap. Now that I have it, I'll stick with the 5.38's. I have a T90A under my '60, and a T90C under my '64. Thanks for your suggestions. Good stuff about the different transmissions.
     
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