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Transmission/T-case Swap

Discussion in 'Early CJ5 and CJ6 Tech' started by Peter Harman, Apr 29, 2018.

  1. May 7, 2018
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

    Medford Mass USA
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    Prior to 1971, Jeep used a GM BOP (Buick-Olds-Pontiac) bell housing with the 225. This was combined with a long input shaft and adapter to mate to the T-86 or T-14. Typically Jeep would stock the GM parts used in their cars under the GM part number, so it's essentially a GM bell. Same part.
     
  2. May 7, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

    DC
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    Thats great news - one of the few times a Man hopes to have the shortest of something.
     
  3. May 7, 2018
    mike starck

    mike starck Member Sponsor 2019 Sponsor

    salem,oregon
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    The jeep version of the BOP bell has a left hand starter bulge deleted and the part number cast in that section. I have sold a few BOP bells with the starter bulge on both sides and it really doesn't effect the use on a jeep.But if your going 100% correct you will pay more for the jeep version usually.
     
  4. May 7, 2018
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    :lol:
    If you have the stock 1971 bellhousing, it won't work. The 66-70 V6's used a standard GM bellhousing with an adapter plate as mentioned above but in 71 they went to a one piece unit with no adapter.
     
  5. May 7, 2018
    Twin2

    Twin2 wasn't me Sponsor 2019 Sponsor

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    one other note . the BOP bell housing double hump . doesn't play well with the frame mounted master cylinder
     
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  6. May 7, 2018
    y2grey

    y2grey Member

    Fayetteville NY
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    The ford t18 can be mated to the GM BOP bell housing without an adapter by some re-drilling and machine work etc. it will be the shortest combo. The 77-79 jeep t18 requires a 1 inch adapter plate to take up the extra input shaft length if you don't want to change out the shaft.
     
  7. May 7, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

    DC
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    Sorry what won't work?
     
  8. May 7, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    Yeah the trans should mate right up with some minor modifications to the T18.
     
  9. May 7, 2018
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    The T18 won't work with the 1971 bellhousing
     
  10. May 8, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    Thanks for telling me. Would have been a bear to get under there and wrestle a T18 for 3 hours only to wonder why it won't fit :lol:

    Any idea if my current bell can be modified to work with the T18 or do I need a 70 and older bell? What would be the shortest years and models for the bells if I have to go hunting?
     
  11. May 8, 2018
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    You need the 66-70 version
     
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  12. May 8, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    Is there an adapter that is a separate piece of the 66-70 bell that I should be getting with the bellhousing?
     
  13. May 8, 2018
    Warloch

    Warloch Did you say Flattie??? Staff Member Sponsor

    Falcon, CO
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    No - you just need the older BH - the Adapter is only needed if your using a T90/T86.

    You can also look at Novak and AA. They offer some BH with the work already done to them. I got one for the SM465 machined and ready to go the first time I did one so I knew what to do from there forward.
     
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  14. May 8, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    I see advance adapters has a bell I could use. As long as the stock bell and the T18 input length work I don't mind the work thats required to the T18 to make it mate. From what I see on the Novak site the stock non-71 bell and the Ford T18 will work.
     
  15. May 9, 2018
    Warloch

    Warloch Did you say Flattie??? Staff Member Sponsor

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    Correct - my process was to modify the T18 case and bearing retainer. Used the Ford input and Jeep output w/plate - did a rebuild on the tranny while swapping the parts.
     
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  16. May 10, 2018
    Peter Harman

    Peter Harman New Member

    Fountain CO
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    Waaaaait a minute... I see what you did there! (y)
     
  17. May 10, 2018
    Norcal69

    Norcal69 Out of the box thinker 2019 Sponsor

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  18. May 10, 2018
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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  19. May 13, 2018
    whateverpratt

    whateverpratt New Member

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    I've been contemplating a 4 speed swap for the future as well, but I haven't been able to decide between the sm420, sm465, or the t18. Does anyone have the lengths of these different transmissions mated to a dana18? My first thought was the sm420 because I think it will bolt right up to the buick bellhousing, but then I saw the sm465 adapter was only 1 inch long. Now I'm wondering if a frankenstein t18 would be the best option
     
  20. May 13, 2018
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    I believe Novak gives you that information on their site. Novak Conversions Home

    The two GM Muncie transmissions (SM420, SM465) will bolt up to a GM bell without modification (mostly). The Ford transmissions (T-18. T-19, NP435) will bolt up to a GM bell with minor machining. Novak covers all of this on their site - just keep following the embedded links on their site and you will cover the issue completely.
     

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