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1966-1971 V6 4 speeds - requesting opinions

Discussion in 'Early CJ5 and CJ6 Tech' started by dal290la, Jun 17, 2014.

  1. Jun 17, 2014
    dal290la

    dal290la New Member

    Abingdon, MD
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    Which 4 speed transmission was the best used with the dauntless between 1966 and 1971 and why?

    What about the 3 speed with over drive?
     
  2. Jun 17, 2014
    duffer

    duffer Rodent Power

    Bozeman, MT
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    For the V6's, there was only one option-the T18 and I believe all of those were the 4.02:1 first gear. The three speeds included the T86, T14, and T15, the latter for 71 only. The T86 is not usually considered in any way desirable and is nothing more than a slightly tweaked T90 with a case pattern like the T14 and T15. For reasonable use, nothing wrong with the T14 (except maybe the 10 spline output), the T15 is significantly more beefy. With a D18 transfercase, an overdrive can be used with all but that is not a stock item and all those transmissions have a 1:1 top gear.
     
  3. Jun 17, 2014
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    I agree with what Duffer said, except I don't think the T15 ever came stock behind the v6.
    4 speed swaps are common....usually the T18, or the Muncie SM420 or SM465.
    Swapping has been covered a LOT on here, do a search, read up on it, also check out the Novak & Advance Adapter websites.
     
  4. Jun 17, 2014
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Yeah, the 225 V6 never got the T-15 3-speed. First year for the T-15 in CJs and Commandos was 1972, and only with the 304 V8.

    The T-15 used with the 304 is the same bellhousing bolt pattern as the T-14 and T-86, but the input shaft is too long. It will bolt up to the Dana 18 if you use a compatible 6-spline input gear. Strong transmission - very much up to the 225's output. Novak (and Advanced?) sells an adapter.

    Your post is quite vague. Do you want a discussion of the relative merits of each factory transmission?
    http://jeeptech.com/trans/t86.html - parts are scarce, but there are work arounds. Very similar to the T-90.
    http://jeeptech.com/trans/t14.html - used later, and preferred to the T-86.
    http://jeeptech.com/trans/t18.html - close-ratio only, and very very scarce, only in the last few years.

    Look at the Novak site for additional articles about these transmissions. http://www.novak-adapt.com/index.htm

    Yes, what about the 3-speeds with overdrive? The overdrive is an accessory that only works with the Dana 18 transfer case. There is some discussion here - http://hermtheoverdriveguy.com/
     
    Last edited: Jun 17, 2014
  5. Jun 17, 2014
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    You really don't say what your primary intended use is. For crawling, you will want something with a compound, or "granny" first gear. Otherwise, just about any four speed can be made to fit. I used to have a T18 years ago which was a good choice.
    My current '66 w/Dauntless 225 has an alloy-case Muncie M20 out of a '60s muscle car. The ratios are closer than usually found in Jeeps, and the shifter is on the drivers side of the tunnel , but it works pretty well for all-around use. I'm working on a Warn overdrive to go on the back when I get a few more parts.
    -Donny
     
  6. Jun 17, 2014
    Wenaha

    Wenaha Member

    West Coast
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    I am (slowly) building a 225 V6 powertrain. I have an SM420 in my shop, but now plan on using the wide ratio Ford T18 with a Dana 18 TC. I will use an Advanced Adaptors bell housing to mount the T18 to the Buick engine.
     
  7. Jun 17, 2014
    dal290la

    dal290la New Member

    Abingdon, MD
    Joined:
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    Ok thanks for all the great info but why did no one mention the T-98? I heard this was used behind the V6 with a D18 case as an option. It was a 4 speed with unscync 1st gear.
    An what is up with the unsynchronized 1st gear? When was this changed for synchronized gears and which transmissions employed? I greatly dislike the T98 with unsynchronized 1st.

    Novak says:
    The T-18 was optional on CJs from 1971-1979. The T-18A version used from 1977-1979 is the best transmission ever put in a CJ by the factory since it features a granny low first gear(6:32:1.) Earlier T-18s have the same great strength, but a 4.03:1 first. The T-98 is the predecessor to the T-18 that was an option for CJs from 1955-1970. But................
    The T-98 has a very similar appearance to the T-18 except a casting number of T98. It is heavy duty like the T-18, but a bit more prone to wear since bearings and lubrication are not as good. Internals from a T-18 can be put in a T-98 case.
    Other Jeep trucks also had the T-98 as an option from 1955-1970, the close ratio T-18 optional from 1971-1975, and the wide ratio T-18 from 1976-1979. After 1979, the wide ratio T-18 was only avilable as an option in the J-20 pickup truck from 1980-1981. This version of the T-18 has the round New Process bolt pattern and 23 spline output, but the adapter is long for a short wheel base Jeep. Earlier T-18s and T-98s used the "Texas" bolt pattern and 6 spline output. The truck version of the T-18 uses a long input shaft compared to the T-98 or CJ T-18s.[TABLE]
    [TR]
    [TH]Transmission
    [/TH]
    [TH]1st
    [/TH]
    [TH]2nd
    [/TH]
    [TH]3rd
    [/TH]
    [TH]4th
    [/TH]
    [TH]Rev
    [/TH]
    [TH]
    [/TH]
    [/TR]
    [TR]
    [TD]T-98
    [/TD]
    [TD]6.40
    [/TD]
    [TD]3.09[/TD]
    [TD]1.69
    [/TD]
    [TD]1.00[/TD]
    [TD]N/A
    [/TD]
    [/TR]
    [TR]
    [TD]T-18
    [/TD]
    [TD]4.02
    [/TD]
    [TD]2.41
    [/TD]
    [TD]1.41
    [/TD]
    [TD]1.00[/TD]
    [TD]4.73
    [/TD]
    [/TR]
    [TR]
    [TD]T-18A
    [/TD]
    [TD]6.32
    [/TD]
    [TD]3.09
    [/TD]
    [TD]1.69
    [/TD]
    [TD]1.00[/TD]
    [TD]7.44
    [/TD]
    [/TR]
    [/TABLE]
     
    Last edited: Jun 17, 2014
  8. Jun 17, 2014
    duffer

    duffer Rodent Power

    Bozeman, MT
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    To my knowledge, the T98 was never used with anything other than the F/L 134 bellhousing and I don't believe there was a long input version for a conversion. The T18 is really just an improved version of it that was used in all sorts of applications so there are a lot of part combinations you can put together.

    If you need adapters anyway, I would go with the Muncie SM465 as that makes the shortest package I'm aware of. You would need to get the 225 bellhousing or adapter machined to fit the big index on the Muncie but otherwise it will bolt up. The Muncie SM420 has a better low gear and will bolt up but the adapters make a longer assembly and the right side bulge make for some cast iron grinding to get it to fit.
     
  9. Jun 17, 2014
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Yes, the T-98 was never offered with the 225 V6.

    If you demand a synchromesh first gear, your only option from the truck 4-speeds is the Borg-Warner T-19. It was never offered in any Jeep, so it's only available by conversion.

    Otherwise, only the passenger car transmissions offer four forward speeds and a synchromesh first. You normally would not use the super-low first around town with a truck 4-speed, and you'd never downshift into super-low first, so there's really no point in making that gear synchromesh. Have you driven a truck with one of these transmissions? They are basically fully-synchromesh 3-speeds with an auxiliary super-low gear.
     
  10. Jun 17, 2014
    dal290la

    dal290la New Member

    Abingdon, MD
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    In reading additional info, it seems that it could be special ordered with the CJ but does not identify years or power.

    "The T98 transmission is a heavy-duty, top loading, truck style four-speed. The Borg-Warner T98 transmission was introduced in 1948 and persisted until 1964 in Ford trucks. It was installed into Jeeps starting in 1955. The Jeep T98 was a desirable, but rare option for Jeeps through 1972, as it was a special order item for civilian versions. It was more common in military versions of the CJ like the M38A1. "
    [TABLE="align: right"]
    [TR]
    [TD="class: boxtext_gray"][/TD]
    [/TR]
    [/TABLE]
    The Borg Warner T98 was distinctively the first compound-low, four-speed manual transmission to be offered in Jeeps. This transmission was standard in the Kaiser Jeep M715 and M725 military trucks. It was also found in IH, Reo/White, other trucks and industrial applications.
    The T98 is a good, tough transmission, and all consumable parts are available as well as most hard parts. Key parts like Jeep version input shafts are difficult to find and interchange, so individuals hoping to mix and match different versions for conversion and adaptation purposes often find it to be a frustratingly long and expensive experience.
     
  11. Jun 17, 2014
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Only with the 4-cylinder, not with the V6. And it ended in 1971, not 1972, with the end of the F134 CJs for domestic sale.

    The F134/T-98 combo was right there on the option list with the F134, AFAIK. Not a special order. Not rare. Actually fairly common, way more common than the V6/T-18 combo.
     
  12. Jun 17, 2014
    duffer

    duffer Rodent Power

    Bozeman, MT
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    I really don't think the T98 was an often selected option even with the F head-I'm guessing low single digit percentage sales. At least with the F head, you could actually use that granny low occasionally. With the V6's and a 4.02:1 low gear, the T18 didn't offer much more utility than the 3 speeds. It's biggest advantage there was it stayed together way better than the T86.
     
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