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Budget Trans Options For A Gm Bell Housing?

Discussion in 'Early CJ-5 and CJ-6 Tech' started by 70cj5134f, Feb 7, 2019.

  1. Feb 8, 2019
    70cj5134f

    70cj5134f Member

    East Tn
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    Still confused! Don't have a lot of $$$ to use. The engine is long, but I'm setting it forward and was hoping to use stock trans location. Tires are 32 x 11:50 . They measure just a tad over 30.
    I need new tires soon. Was planning on a little narrower 31 or 32. May have to use drivetrain I have and take it easy on the skinny pedal!
    I'll keep researching until time to install.
    Thanks
     
  2. Feb 8, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    This is not a topic you can be expert in without some reading and research. Here are some hints to direct your search.

    Transfer case adapters are expensive. Your best option if you want a cheap 4-speed is to find a T-18 from a Jeep vehicle that can already bolt up to your transfer case. The Muncie transmissions (SM420, SM465) will bolt up to a GM bell but require an expensive transfer case adapter. The engine end is simpler and cheaper to adapt.You can combine parts from a Ford and Jeep or IHC T-18 to make a transmission that wil work. There were T-18s in CJs with the V6 in 1971, but they are very scarce.
    The Novak Guide to the Adapting Ford Style Transmissions to GM Engines
    Mix the Ford case and gears with the Jeep main shaft and adapter to make a transmission that will work with a GM bell and a Jeep transfer case. This has been covered many times here if you search.

    Consider the Borg-Warner T-15 three-speed. Must be adapted to the GM bell, but it will bolt up to the Dana 18 if you use the right output gear. If you are good in the machine shop, you can make the adapter. 6 splines, same as the T-90, so you can use your T-90 output gear. Strong, easy shifting, made to withstand V8 power. Not hard to source. Engine adapter is comparatively cheap, if you have to buy it. NOT the T-150 - that's also a good transmission but not suitable for the Dana 18.
    The Novak Guide to the Borg-Warner T15 Transmission
    Adapting the Chevrolet & GM Standard Shift Bellhousings to the Jeep CJ & FSJ Borg-Warner T14, T15 & T18 Transmissions
    I'm a bit of a fan - my CJ has one as does my J-10. Ken is too. T15 To Dauntless There is plenty more about the T-15 in these forums if you search.
     
    Last edited: Feb 8, 2019
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  3. Feb 8, 2019
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    The small bore 18 tcase that the OP has behind a T90 won't bolt directly to a T15. It would have to be a large bore 18 case, or a model 20 case with the 18 internals.
     
  4. Feb 8, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    According to the Novak table, all the CJ-5s with a 4-cylinder have the 1.25" shaft case with the 809297 input gear. Can you use the Dana 20 case with these gears? I presume the large bore 18 was used with the T-14 and V6, and it would not work with a T-15 because it has 10 splines. SOthat would be a guts-swap too. A Dana 20 should be cheap to source. Would the small-bore 18 work with a T-18?
     
  5. Feb 8, 2019
    ITLKSEZ

    ITLKSEZ Volvophilic

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    Might need the adapter plate from a T98? :shrug:
     
  6. Feb 8, 2019
    Sierra Bum

    Sierra Bum Member

    The High Sierra
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    The truck four speed swaps are going to cost $. Some creativity can save some money. But there’s driveshafts, linkages, the floor and unforeseen challenges. The T18 is great...be aware of all the different ratios out there. Not all of them are true granny boxes if that’s what you’re after. Maybe the 4 speed is a better long range goal.
     
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  7. Feb 8, 2019
    70cj5134f

    70cj5134f Member

    East Tn
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    Ok, I'm confortable with any labor I can do to adapt, trans parts swap, using some out of 1 into another, or mix of any kind. If I understand correctly?
    1- I can find a T18 and it will bolt to everything but engine?
    2- if I use a T15 it requires some work to bolt to T-case?
    3- I don't want a side shift, must be a top shift.
    4- Someone please make me a simplified list of easiest to hardest to adapt!
    Is the T18 the simplest to install, and locate?
    Ps- I would think the Fuse that breaks would be my tiny u-joints, driveshafts,and axels-not the T90? (If shifted correctly). What part of the t90 breaks under abuse?
    I do want to be able to sling mud, not so much jumping and getting air?
    And how does my 200hp, 300tq, compare to a well tuned v6?
    Did the v6 Cjs have larger u-joints, driveshafts and axles?
     
  8. Feb 8, 2019
    Jw60

    Jw60 Recovering Jeepaholic

    Sedalia MO.
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    A stock 2000s 4.3 is around 200hp and 260tq.
    I beleave a stock v6 has a smaller joint on the front for clearance.

    T18 came bolted to jeep Dana 20s and Ford engines. You take the jeep output shaft, adapter plate and Dana 20 case and rebuild the Ford case (make sure it is the wide ratio 6:1 unless you want a 4:1) with the jeep output shaft. Then rebuild the D20 case with the D18 guts. If you have access to those hard parts it is a matter of rebuilding everything and new driveshaft.

    Sm465 is a matter of buying the kit and rebuild with that there aren't any cheaper ways unless you find a lost project.
     
  9. Feb 8, 2019
    Sierra Bum

    Sierra Bum Member

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    The 5 or 6 truck 4 speed trannys... and the top three in no particular order are:

    SM420 GM; The most compact gear box. 7:1 first gear. Both 2wd and 4wd versions work. Common swap for GM Bell's. Oldest design. Can be hard to find internals for a rebuild.
    Or...
    T18 Ford, Jeep, Dodge (?); 4:1 or 6.32:1 first gear. Lots of variations. Know what you're looking for.
    Or...
    SM465 GM; 6.5:1 first gear. Both 2wd or 4wd versions will work. Make sure your bell housing will accommodate the large input shaft bearing retainer. The 1" adapter by Novak and it's easy availability makes this an attractive option.

    NP435 Ford: 6.5ish:1. Great box for Ford Bellhousings and popular with the Bronco crowd.
    T19 Ford, Dodge: Similar to T18. 4:1ish fisr gear
    T98a Jeep, Ford(?). Early version of the T18

    More Psychobabble and Ideas:
    If you can find a Ford T18 with a 6.32, I have heard that's the "easiest". Many of the Jeep T18's have a 4:1 first gear. They will all be work, require some adapting somewhere and some $ to do it cleanly and correctly. Lots of folks just use what comes to them as they are all good transmissions. I have done two SM420 swaps to 225 V6's, so that's what I can speak to. The large hole dana 18 with the V6 uses small U joints for the front driveshaft. The adapter and the driveshafts are the pricey parts. Advanced Adapters and Novak makes the adapters. You might find out if they have "seconds" available. I had the run of a Jeep wreaking yard when I was a kid and we pieced together a couple drive shafts for a swap once for cheap, and they worked fine. So look into that. The dana 18 will take an OD which is a very cool classic feature and a major benefit in an old Jeep. Lastly, take and calculate the various drive train length measurements and compare with the possible combinations.
     
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  10. Feb 10, 2019
    70cj5134f

    70cj5134f Member

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    Unless I hit the lotto, or a relative remembers me in his will,I'll be using what I have for now.
    Seems the simplest and most $ friendly solution. Maybe later upgrade the drivelive?
    What part of the T90 breaks? Are their upgrade parts available?
    When I tear it down, anything special to look for, or mod? I'm going to mod something to stop the drip(sometimes flood).
     
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  11. Feb 10, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    The T-90 will be ok. Treat it right - no burnouts, no speed shifting (always lift the throttle when shifting) and don't grind downshifting into first. I believe there is no one part in the T-90 that breaks; about the only upgrade beyond fresh parts is a sealed front main bearing to keep them from leaking out the front bearing retainer.
     
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  12. Feb 10, 2019
    Rich M.

    Rich M. Shoe pusher

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    No fun!
     
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  13. Feb 10, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    I think the most common wear problem is the bushing inside 2nd gear. It rides on the main shaft and, if loose enough, the gear bevel makes it skew on the shaft. This pushes the synchro collar away from the gear and makes it pop out of gear when decellerating. New 2nd gears are available.
     
  14. Feb 10, 2019
    70cj5134f

    70cj5134f Member

    East Tn
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    So burnouts in mud are ok, I was not planning on hard use on hard pack. Most of my adrilin will be let go in the mud,snow, and other low traction circumstances ?
    I try to not grind 1st, can usually slightly rev engine, while double clutch in and hit 1st with no noise?
    I still think the ,u-joints ,or shafts would go before tq twist the gears?
    No pavement burst of speed necessary, I have a 455 in a beater for that!
    Thanks all!
     
  15. Feb 10, 2019
    colojeepguy

    colojeepguy Colorado Springs Sponsor 2019 Sponsor

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    1st& reverse in a T90 are reasonably stout, that big sliding gear and four sets of roller bearings on the cluster gear. It's 2nd& 3rd that take a little care....as mentioned don't shift it too hard.
     
  16. Feb 11, 2019
    70cj5134f

    70cj5134f Member

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    Am I going to need another input shaft for my GM bell?
     
  17. Feb 11, 2019
    Jw60

    Jw60 Recovering Jeepaholic

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    I was digging thru the engine build for dimensions to make a cad model of the pilot bearing holder
     
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  18. Feb 11, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    Maybe. There are two styles of adapter, one uses a new shaft with a thick adapter and the other does not, with a thin adapter. Both are shown on the Novak site. The main problem with the short-shaft version will be firewall interference, which maybe is not an issue with another 4-cyl.
    The Novak Guide to the Borg-Warner T90 Transmission
    Adapting the Chevrolet & GM Standard Shift Bellhousings to the Jeep T90 Transmission

    These adapters show up on the used parts market pretty often, if you want to save some money. For example
    T90 Jeep transmission to GM bell housing Adaptor | eBay
    This one needs a long shaft and bearing retainer. Ask around if you are interested in finding a used adapter.
     
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  19. Feb 11, 2019
    70cj5134f

    70cj5134f Member

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    I had the crank drilled for a stock dia. F134 pilot bushing if this helps?
    Thanks for the time u spend to help!
     
  20. Feb 11, 2019
    70cj5134f

    70cj5134f Member

    East Tn
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    Firewall will be ok, worried the stock input might not reach the pilot In the gm bell?
    If room allows, I can locate the pilot In the flywheel! Might interfere with clutch disc?
    Not all, but several of the installs have machined 5/8 off the back of block, I don't want to do this!
     

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