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T18 swap

Discussion in 'Intermediate CJ-5/6/7/8' started by dmcgaha, Mar 1, 2006.

  1. Mar 1, 2006
    dmcgaha

    dmcgaha New Member

    Prairie Village, KS
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    I am picking up a Jeep T18 wide ratio this weekend. I have seen a few posts on others doing this swap. Anyone with any idea on what I am getting myself into please educate me. I have a 1974 with 304 and t15 in it currently.
     
  2. Mar 1, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

    North Texas...
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    You can use the t-15 bell housing with a little modification and the bull gear on the tranny output should be fine to use with the t-18. If the T-18 is out of a J series truck then you will need to do a short shaft conversion on the tranny. Otherwise it will be too long for a 5. Does the T-18 have the adapter plate for your t-case on it?

    In other words, there are several of us who have done this with both AMC and Ford t-18s so ask away.
     
  3. Mar 1, 2006
    dmcgaha

    dmcgaha New Member

    Prairie Village, KS
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    I have seen the short shaft conversion from Novak, is that a good one?

    It had a d20 on it so I hope that it still has the adapter. If not is there somewere to get them. I see them for the Ford T-18 will that work for the Jeep one?
     
  4. Mar 1, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

    North Texas...
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    Unless the PO took the adapter off it should still be there. If not you should be able to get one from novak or AA. If the bull gear is missing from the tranny then make sure you get the spacer that goes between it and the tranny. It is 1.5 inches long and machined to fit over the shaft and through the seal on the adapter plate. Without out this spacer you can not tighten the bull gear down. Mine was missing and I had to have one machined.

    I got my short shaft from Parts Mike in California. It is an easy install to do. Make sure you get the Pilot bushing as well. The short input shaft is actually from a ford and the end is smaller then an AMC input shaft.

    http://www.partsmikeparts.com/
     
  5. Mar 1, 2006
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Hudsonhawk, are you thinking of the T-150 bellhousing? I don't think the T-15 bell will work, both because of the pattern and because of the depth. I had understood that the T-150, which is a Ford pattern transmission, will work with the Jeep T-18 if you drill it. The Ford T-18 will bolt up to the T-150 bell with no mods, and the Jeep T-18 is only different by one bolt hole (which can be drilled).

    The T-150 and T-176 bells are Ford pattern, and the SR-4, T-4, and T-5 bell is the same casting (I think) and can be redrilled to the Ford or Jeep pattern.

    If the D20 is still bolted up, you can sub your D18 with no additional adapter as long as you get have the right bull gear to match the transfer case. There's a table on the Novak site that describes what gears fit which transfer cases.
     
  6. Mar 1, 2006
    kamel

    kamel Senior Curmudgeon

    Erlanger, Kentucky
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    regarding the short input shaft.

    It would be a Ford t-98 short input shaft??

    I understand from AA that the shaft is a t-98 shaft and therefore it can be used in a T-18 or T-98 with the only difference being the roller bearings (size and quantity) that are used.

    I'd be curious if anyone has the part number for the Ford input shaft that AA sells.

    Ithink it would be t98a-16, but I am not sure.

    kamel
     
  7. Mar 1, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

    North Texas...
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    DOH! your right. I meant the T-150 or T-176 bell housing. :(

    The output shaft on the t-15 is the same size and spline count as a t-18. The current bull gear should swap directly over.
     
  8. Mar 2, 2006
    dmcgaha

    dmcgaha New Member

    Prairie Village, KS
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    So I will need a short shaft kit and a bellhousing from a t-150. How about clutch? I have read that my current clutch will work and other places that it will not.

    I am also attempting to put tera low gears in my t-case as well. I was looking at the heavy duty output shaft too, will I have enough room for that. Is it even worth it?
     
  9. Mar 2, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

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    I am thinking the clutch linkage you have should work. But I am not sure. I upgaded from a t-14 not a t-15. In my case There was a cable actuated clutch that I removed and replaced with a hydraulic master and slave. I had to change out the throwout arm with one from a t-150 to accomodate the hydraulic slave cylinder.

    You will have to replace the clutch disk with one that matches the new input shaft.
     
  10. Mar 2, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

    North Texas...
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    As far as length is concerned. My T-18 is 3 inches longer then the T-14 it replaced. This includes the adapter plate for the t-case and bell housing. You will have to shorten the rear drive shaft to make it work.

    If you are doing rocks or steep hill climbs then the teralow is your friend. I have wheeled mine twice since I installed it. It is amazing how much better if feels in extreme situations.

    I am not sure I would replace the dana 20 output. But time will tell how mine holds up behind the teralows.
     
  11. Mar 2, 2006
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    A '74 will have mechanical linkage (a bellcrank). It should work fine - you may have to use the release arm from a T-150 Jeep (all '76-79 3-speed), but I'd guess not.
     
  12. Mar 2, 2006
    iamgeer

    iamgeer Member

    Calgary,...
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    If it is a stock cj t18 '76 or newer tranny your clutch should work fine as it has a 1 1/8 " input shaft, just like the t15. If you install a short shaft kit the input shaft that is used is a Ford input shaft that measures 1 1/16" and you will need a new disc. If you get a t150/t176 bell make sure you get the associated clutch fork and get a new throw out bearing as they are not the same as what have on your t15. Go to the jeepfan website. He has documented a tranny swap of this sort.

    Give the t18 a try without messing with your tcase first. You may decide you dont need the terralow kit.

    Karl
     
  13. Mar 2, 2006
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Regarding the clutch, you need to match the splines on the input shaft of the T-18 to the disk. Your original disk may match the Jeep truck disk - don't know - but it'd be foolish IMO to take everything apart and not freshen up (replace with new) the throwout bearing and the disk. Jeep trucks came with 304s in '71-72 or '73, so just get the disk that matches your engine-transmission combo. I'd also replace the cover if you don't know its history.

    <edit> Ooh Ooh... :oops: you're going to use the short shaft - that's a FORD part, so you'll need a FORD disk. The stock T-150 disk (a FORD transmission) and cover will work fine.
     
  14. Mar 2, 2006
    xlr8n

    xlr8n Member

    Sparks, Nv.
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    I recently swapped a T-18a into my '75 (304/T15). Here is what I used:

    - T18a/D20 donated from a '77 J10
    - '84 bellhousing/clutch fork donated from a I6/T4 (drilled and tapped)
    - Clutch disk for '76-79 CJ
    - Short shaft kit (shaft/bearing/gaskets/pilot bushing) from partsmike
    - Diaphram type pressure plate (used to accommodate throw-out bearing)

    Your existing clutch linkage should work fine.

    The front drive shaft will need to be lengthened while the rear will need to be shortened. I had to go with a CV style in the rear. I also had to reposition the spring perches on the axle to reduce some of the pitch (4" lift).

    I plan on installing the tera-low gears in the D20 but funds are holding me back.
     
  15. Mar 2, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

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    Is there a write up on this in the tech section? There really should be.
     
  16. Mar 2, 2006
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Might try a search if you haven't already. I know sometimes it can be hard to find what you're looking for in the search function though. This has been covered exhaustively in the past. Not too long ago either Jpflat2a or Timgr put a link in another similar post that covered most of this info.
    Part of what you will need to do will depend on which transmission you are starting with. There are around 12 different input shaft lengths for a T-18. The Ford input is by far the shortest and best route using the '76 up bellhousing as mentioned. R&P can also supply you with all the parts you will need for this as they normally stock everything including the hard to find rubber mounts, machined pilot bushings, etc. Can be reached at 503-557-8911. They can probably supply you with a used adapter plate if the tranny you get doesn't have one, as well as the necessary spacer and seal. Be aware there are two synchro sizes and the input needed will depend on which one you currently have. Fords came with both sizes. The most common in the ford is the thin synchro, but I've found many Jeep T-18's use the thick synchro. Sorry but don't have part #'s handy. Nickmil.
     
  17. Mar 2, 2006
    73CJ89XJ

    73CJ89XJ Heeper

    York, PA
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    What throwout bearing is everyone using? The T18 shaft is larger than my current T14. I have a jeep bellhousing and jeep T18a.
     
  18. Mar 2, 2006
    hudsonhawk

    hudsonhawk Well-Known Member

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    I used the throwout bearing off a t-150 same as my bell housing and clutch fork.
     
  19. Mar 2, 2006
    xlr8n

    xlr8n Member

    Sparks, Nv.
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    Since I used the bellhousing and clutch fork from a 1984 Jeep I6/T4, I used the throw-out bearing for that setup. I also went with the diaphram pressure plate for a '75 (purchased to match my flywheel) as I was told the throw-out bearing would ride better on it than the original fork style PP that I had.
     
  20. Mar 3, 2006
    dmcgaha

    dmcgaha New Member

    Prairie Village, KS
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    I picked it up today. The guy that was supposed to get the tcase never showed up so it still has a d20 attached. It is also marked with T18-1B on the side, I hope that this is the right one. I will try seeing how many turns of the input shaft rotate the output shaft once I figure out how to get it out of the back of the car:/

    Should I try finding the bellhousing used or whould it be better just to get a new one?
     
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