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3-speed TC gears in a 4-speed TC

Discussion in '40- & 55-Series Tech' started by hammerhead, Nov 20, 2003.

  1. hammerhead

    hammerhead

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    Am switching to an SM-465 transmission with 3-speed TC gears. I want to know if I can put the 3-speed gears and such in the 4-speed case being the stronger case. Or should I just put my 4-speed TC parts on the 3-speed case?
    Thanks.
    E
     
  2. cruiser_guy

    cruiser_guy

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    Why not run the 3 speed case and if you grenade it then you can swap. If you don't grenade it then you've saved a ton of work!
     
  3. hammerhead

    hammerhead

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    I thought of that too but I hate being towed in. I'm hoping I never need to fix anything worse than a birf out in the rocks. Just trying to do the best possible job I can since I have both 3 and 4 speed tranny/t-cases. If it's a drop in to put the 3spd gears in the 4spd case then it should be worth my time. That is if the 4spd case is enough of an improvement to make it worthwhile.

    E
     
  4. willsta2000

    willsta2000

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    I believe if it's a transitional t-case (early 74,... possibly 73 as well), you can just put the input gear in your 4-speed t-case.
    Granted, I'm definitely not 100% sure of which t-cases let you do this,... but I put the 10 spline input gear from an early '74 t-case into my late '74 (16 spline) t-case,... it fit perfectly, + saved me a bunch of time.


    Hope this helps
    WILL
     
  5. 76FJ40

    76FJ40 Old Fart SILVER Star

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    There's a great article in the tech section on T cases. The 3 speed and the 4 speed have different internal dimensions so you'll have to shim to make the swap work.
     
  6. woody

    woody unhelpful spotter Staff Member Admin

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    what year is the 3-speed case? My 72 has yet to break with an Amway t-case saver on it...and I'm NOT easy on my rig either....
     
  7. red66toy

    red66toy dorkus malorkus GOLD Star

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    Where do you get those T-case savers? Thanks.
     
  8. hammerhead

    hammerhead

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    Woody - it's a '69 3spd t-case. Will it survive rockcrawling?

    76 - I'm pretty sure I read everything in tech but didn't find any mention of this swap.

    How hard is it to shim up? Is that the only mod required?

    E
     
  9. Vortec_Cruiser

    Vortec_Cruiser

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    The swap is very easy to do. The only difference is the need to shim the idler gear, since the 4-spd case is wider due to wider gears. The shims are standard Toyota shims, and the adjustment is outlined in the Toyota manual. ::) I put '69 gears in my '77 case, and also used the Anway brace. ;)
     
  10. willsta2000

    willsta2000

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  11. woody

    woody unhelpful spotter Staff Member Admin

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    I removed my 69 case after 3 hard years and installed a 72 one, since I had similar concerns. I never did break the 69....honestly, if you A> run the t-case saver, and B> a GOOOOD skid plate that protects the entire t-case from any shock hits while crawling, I wouldn't expect any problems.

    However, if you have the parts to strengthen, or to go with a newer case, I'd do it.
     
  12. MD11Fr8Dog

    MD11Fr8Dog CM09 Eight Ball winner

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    [quote author=hammerhead link=board=1;threadid=7849;start=msg65975#msg65975 date=1069386288]
    Am switching to an SM-465 transmission with 3-speed TC gears. I want to know if I can put the 3-speed gears and such in the 4-speed case being the stronger case. Or should I just put my 4-speed TC parts on the 3-speed case?
    Thanks.
    E
    [/quote]

    Putting the 3spd gears into the 4spd case is pretty easy. I did it last spring also using the 4spd output shaft and the 4spd nose cone! You just need to get the shims to shim up the idler cluster, since the 3psd gear set is narrow!
    http://board.marlincrawler.com/index.php?board=16;action=display;threadid=1189
    [​IMG]
    [​IMG]
     
  13. Vortec_Cruiser

    Vortec_Cruiser

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    Sean, the 3-spd gears are not narrower. The 4-spd gears are wider. :flipoff2: