manual 3 speed to 4 speed

Discussion in 'General IH Tech' started by IH1300, Oct 17, 2005.


  1. IH1300

    IH1300 Farmall Cub

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    What Will I Have To Change Out To Do This ?
     
  2. stu simpson

    stu simpson High Wheeler

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    please expound in detail about the application i.e. scout, pickup, 2wd, 4wd, year
     
  3. IH1300

    IH1300 Farmall Cub

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    1979 Scout Ii 304 3 Speed Manual . I Wondering If The Bell Housing ,cross Member, Have To Change Out To Go To A 4 Speed . I Have To Put A Clutch In It Anyway Thought It Would A Good Time To Do It . But I Do Not What All Will Need Replaced Or Changed? Thanks Mark Sorry About No Info.
     
  4. IH1300

    IH1300 Farmall Cub

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    It`s 4 Wheel Drive
     
  5. IHREDRIDER

    IHREDRIDER Farmall Cub

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    Bellhousing from a 3 sp to a 4 spd in a Scout II is different.

    If you get a 4 spd, bellhousing, clutch bell joint from a scout I that should be enough. I'm not sure on driveshafts, but I suspect they are different lengths.
     
  6. scoutmstr

    scoutmstr Farmall Cub

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    I bought my '78 Scout II 304 3 speed in '79. Installed a wide ratio T-19 in '80 directly from Borg Warner. Nothing changes except shift lever is different. All else is exactly the same. I got the blueprints from Borg Warner because back then no one including IHC could tell me what 4 speed to buy from Borg Warner. The 3speed has a shorter case but uses an tail extension so OAL is same. I had no problem with the bell housing.
     
  7. stu simpson

    stu simpson High Wheeler

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    As long as the stuff is out of another v8 SII, you are ok. There will be issues if your original/donor bellhousing came from a Scout 800 or a 4cyl SII. I totally know nothing about 6cyl applications. A v8 T90 in a Scout 800 has a different bellhousing to tranny bolt pattern than a SII v8 T90. For SII, the T90, T18, T19 etc bolt patterns are all the same. I would still save any bellcrank, pivot, shaft and fork assembly etc from any donor vehicle just in case. I have found that a truck 4sp bellhousing is OK for the Scout 800 v8 4sp conversion if you swap in the T90 (really, Scout 800 manual tranny) bellguts.

    As mentioned, the tailhousing between the T90 and D20 is the difference in length between a T90 3sp and a T18 4sp so your shafts should be close. I don't know about SII tranny crossmember mods that might/might not be needed.

    Also as mentioned, the shift throw is different so you may need to cut a little out of the hump. Not sure though.
     
  8. IH1300

    IH1300 Farmall Cub

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    thanks , information is great , now the hunt is on for a donor ! thanks again mark.
     
  9. Greg Marshall

    Greg Marshall Farmall Cub

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    I did the same on a 71 sII. It already had a mounting place for the crossmember to be moved back. Fit perfectly. The driveshafts are all the same due to the different spacers between the tranny's. I'm not sure if my 79 had the same thing.

    Greg
     
  10. hillbilly68

    hillbilly68 Farmall Cub

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    I did it on a 73 scout II, went from the 3 speed to a T-19 wide (4 speed) and used the same bell housing, I did have to modify the cross member and use a GM transmission mount but it was no big deal.......
     
  11. IH1300

    IH1300 Farmall Cub

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    Hillybilly ,you Used Your Stock 3 Spd Cross Member ,also What About The Trans Shifter Cover Inside Any Mods There ? Thanks Mark
     
  12. hillbilly68

    hillbilly68 Farmall Cub

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    Yes I used my stock 3-speed crossmember, and the same cover plate in the cab, no problems just had to use a gm trans mount, but I only did that so I would'nt have to drill new holes in the crossmember, you can use your same trans mount but I think you will have to drill new holes. the cover plate worked just fine in the cab with no mods
     

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