1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

1976 Fsj T18 Behind My 225 V6?

Discussion in 'Early CJ5 and CJ6 Tech' started by Broylz, Apr 17, 2017.

  1. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    Is it possible to swap a Jeep FSJ t18 into my 225 equipped 70 cj5? I currently have a T14 and D18 combo. the T18 comes with a D20 which will go well with my centered Wagoneer rear D44 axle...
     
  2. Apr 17, 2017
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
    Joined:
    May 25, 2006
    Messages:
    2,871
    If you cut the grill, move the radiator forward, move the motor up as far as possible it will give you a rear driveline about 12" long. The J truck t18 has a 5" spacer which made the setup the same length as the turbo 400 and 20. Not optimal in any way but can be done with a 225 and is pretty inexpensive if you use a trans from a 68 to 70 J truck that came behind a Buick 350 it is a direct bolt in. Once again, nothing optimal about it, you have to rework everything and you end up with a very short rear driveline which really limits any real lift in the back.
     
    Broylz likes this.
  3. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    ok. thanks.
     
  4. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    This is from a Cherokee with a 360. Im reading that only the J truck models had the spacer...
     
  5. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    should i be able to simply get the D20 only and swap it straight for my D18 behind my t14?
     
  6. Apr 17, 2017
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
    Joined:
    May 25, 2006
    Messages:
    2,871
    The t 14 output gear has 10 splines internally. The ONLY exception to the Jeep transmissions that used 6 spline output shafts. There are 2 gears for a T14. The 18-8-49 and the 18-8-50. They are 26 and 29 tooth gears. However you would need to consult the Novak interchange chart to make sure that the 20 you have has the same pitch as a 18-8-49 26 tooth gear as there were 26 tooth gears that were both 17.5 degree pitch and a 20 degree pitch for model 20 t-cases. Clear as mud?
     
  7. Apr 17, 2017
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
    Messages:
    6,656
    I ran one of them for years. It was relatively bolt-in with a relocated crossmember and modified floor. It made for a really short rear shaft, but with no lift and limited travel, it's possible.
     
  8. Apr 17, 2017
    gunner

    gunner Member

    Washington state...
    Joined:
    Dec 4, 2012
    Messages:
    596
  9. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    All full-sized Jeeps (Wagoneers, J-trucks, Wagoneer-based Cherokees) with a manual transmission and a V8 have the 5" thick spacer/adapter and a long input shaft. This applies to the 3-speed transmissions too. There is no spacer with a six cylinder engine, other than a thin plate adapter between the bell and a T-18. No adapter of any thickness for a 3-speed.

    IMO you are better off to buy the Ford input shaft kit from Parts Mike (ca $200) and have a reasonable overall length. You will have to modify the Buick bell housing to mate with the Jeep T-18 case, but the Ford input shaft is the right length for the GM BOP bell housing. Or, you can combine the Jeep T-18 and a Ford 2WD T-18 bu using the Jeep output shaft and adapter. Mating the Jeep adapter to the Ford case requires some drilling and hole plugging, according to Nick, but it can be done. Then your Ford case would bolt directly to the Buick bell. Novack has a page about mating Ford transmissions with GM bellhousings.

    Parts Mike: 1T18-SBR T18 short shaft kit Jeep installation (I would recommend them over Advance Adapter)
    Adapting GM bells to a Ford transmission The Novak Guide to the Adapting Ford Style Transmissions to GM Engines
    Gear interchange Dana 18 and Dana 20 The Novak Guide to Dana 18 & 20 Gears Interchange 1941-1979
     
    Last edited: Apr 17, 2017
  10. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
  11. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    Wrong. All V8 FSJs use the spacer. See above.
     
  12. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    The basic idea for this question was to get a Dana 20 for the centered output to run my wagoneer rear axle. I found a T18 and Dana 20 from behind a 360 in a 76 cherokee.

    what i read on another site was the later models with the Dana 300 had the spacer and the D20s did not. The seller says they bolt straight together with no spacer.

    I could care less if i swap the T18 in place of my T14 or not. If so its a bonus, if i can go with just the dana 20 in place of my current Dana 18, that would be fine too.

    If this is not really as simple as im hoping for, i will just keep looking...

    And yes, it gets muddy quickly talking about the different models and years. What woud be the easiest direct swap from my T14/D18 to get a D20? jsut a transfer case from a certain model? or would a transmission swap be necessary due to the output splines on the T14? could i rebuild my 18 as a 20 since i believe the 70 models had the larger cases of the 20s anyway?
     
  13. Apr 17, 2017
    gunner

    gunner Member

    Washington state...
    Joined:
    Dec 4, 2012
    Messages:
    596
    Tim, the Parts mike kit will fit any FSJ T18? Asking because I may be taking a look at one locally I know of for a great price, if that is the case. D20 already bolted up to it.
     
  14. Apr 17, 2017
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
    Messages:
    6,656
    *To be clear, the bolt-in version came from the select few that had the Buick 350.
     
  15. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    There was never a Dana 300 in a J-truck or Wagoneer. Either the site is wrong or you are misinterpreting it.

    For example, my '82 with a T-18 has a New Process 208 transfer case... and a long input spacer. All V8 FSJs with manual transmission have the long input shaft, regardless of transfer case, or transmission.

    [​IMG]

    Wagoneers, Cherokees, J-trucks ... all the same.

    There was never a Dana 300 in a full-sized Jeep.

    Dana 20s are cheap and widely available. Don't get bogged down with the Cherokee T-18 if all you want is a Dana 20 for your centered rear axle.
     
    Broylz likes this.
  16. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    Yeah. Give them a call - very helpful. Realize that the Jeep case bolt pattern is a little different from the Ford case, and you'll have to drill a new hole for one of the case-to-bell bolts.
     
  17. Apr 17, 2017
    Broylz

    Broylz Member

    Gallatin, TN
    Joined:
    Oct 9, 2012
    Messages:
    238
    i was mistaken. They discuss a NP208 and not a D300...
    from www.jeeptech.com/trans/t18.html
    All Jeep T-18s come with a 1" adapter for the Dana 20 transfer case except the T-18 used in 1980 and 1981 J-20 pickups. These trucks used the NP208 transfer case and the adapter for the NP208 is around 9" long and it uses a round bolt pattern. The output shaft of this version of the T-18 is 23 spline. The Dana 20 version of the T-18 has the big hole "Texas" bolt pattern and 6 spline output shaft.
     
  18. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    To connect a Dana 20 to a T-14, the easiest donor would be a '72-75 CJ-5 or CJ-6 with a six cylinder, T-14 and Dana 20, or a '68-73 Jeepster with a V6 or inline 6 and a T-14 and Dana 20.

    The main issue is the output gear. You need a T-14 output gear (transfer case drive gear), that has 10 splines. Look at the chart I linked above. You probably have a Dana 18 with a 18-8-50 output gear. You need a 20 with a 18-8-49 gear.
     
  19. Apr 17, 2017
    gunner

    gunner Member

    Washington state...
    Joined:
    Dec 4, 2012
    Messages:
    596
    Thanks Tim, I'll do that.
     
  20. Apr 17, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    Pretty sure the Texas pattern adapter is iron, not aluminum. The T-18 was available in a J-truck through the end in 1987, AFAIK.

    All V8 FSJs with a manual transmission have a long input shaft. The earlier V8s (327 and 350) have a bell that includes the long adapter. After that, the spacer/adapter is separate from the bellhousing and the transmission (see above). Regardless, these transmissions used with the V8s have a very long overall length, not really suited to a CJ (though it can be made to work, as pointed out above).

    When the Wagoneer and J-truck were first designed, they only had one engine: the 230 cid OHC inline 6. The engine compartment was designed around this engine. When Jeep decided to offer a V8, they kept the engine mounts in the same place and let the V8 engine be further forward than the six, so it would not interfere with the firewall shaped for the inline six. This meant the back of the engine was now about 5" further forward than with a six, and with the existing transmission, the shifter would have come up under the dash. To solve this problem, they built a transmission with a very long input shaft and bellhousing. This moves the shifter back to the same place in the cabin as the six, even though the back of the engine is significantly further forward.
     
    Broylz likes this.
New Posts