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T-18 drivetrain options??

Discussion in 'Intermediate CJ-5/6/7/8' started by ncgamedog, Apr 5, 2011.

  1. Apr 5, 2011
    ncgamedog

    ncgamedog New Member

    Charlotte, NC
    Joined:
    Mar 31, 2011
    Messages:
    24
    So after doing some further digging online...I think I have figured out that I have a T-18 w/ the "texas" pattern and 6 spline output (assuming its the stock trans for the Jeep and I'm pretty sure it is). That kind of throws a wrinkle in my future plans for the jeep.

    I was hoping to swap in toy axles and maybe a 23 spline toy t-case. I like the Toy axles for their strength to weight ratio, the convenience of the drop out thirds, factory 4:10's, and the flanged driveshafts which are super strong. I had also considered a regular d300 with custom toy flanges from Jess at High Angle. The only thing I dont like about the Toy axles is I dont gain any width over the widetrack axles that I have (unless I run an IFS rear and spacers in the front). That makes me lean towards Waggy 44's, but it cost so much to regear them.

    I guess I need to weigh the cost of going waggy's regeared and finding a IH (texas ptn) d300 vs swapping to a different tranny and tcase all together.

    Knowing what my end goal is, can anyone see a better (cheaper) path to take? Since I have a T-18 already, would swapping to the Ford 23 spline version be easier vs say an SM420/465? I need to keep the drivetrain short as possible so I have some rear driveshaft left lol.

    I really hate the thought of dealing with clutch mechanisms and crap, I have been down that road before and it can be really frustrating to get custom stuff tuned in right.

    thanks for any help or insight! -Justin
     
  2. Apr 6, 2011
    Ghetto Fab.

    Ghetto Fab. Member

    Atascadero, Ca.
    Joined:
    Jan 13, 2005
    Messages:
    512
    What is wrong with the d20 t-case? I had the same issue with my jeep and found it was easiest and cheapest to just rebuild it and upgrade to the tera gears. So far so good, we'll see how it does in the buggy.

    My thinking these days is that a d300 isn't that much better than the d20 anyways and unless your going to upgrade to an atlas, stak or 205, its just not worth spending the money on adapters etc...

    I can't argue with wanting a toy t-case. I have a toy also. Tons of gearing and doubler options, but no true twinstick, and it'll add a lot to your drivetrain length.

    Kevo
     
  3. Apr 6, 2011
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    You just want more reduction?

    The factory T-18 for a CJ-5 in 1975 is not a granny gear transmission. Instead, it has the 4.02:1 first gear and is called the "close ratio" T-18.

    You can get a 57% boost in gear reduction (4.02:1 to 6.32:1) by going to a T-18 that has the wide ratio gears. Unfortunately, you can't just put the WR gears in your existing case. Jeep used a few different input shaft lengths, and finding the right input shaft gear for WR may be difficult. You may be able to swap in the gears (or complete transmission) from a Wagoneer or J-truck that has the T-18 and a 258 inline 6, in place of the current CR transmission. Note that the V8 T-18 will not work - it has to be from a six.

    Another option is to find a Ford pickup T-18 (always WR) and mix parts between the WR and CR transmission. Use the main shaft and adapter from the Jeep T-18, and the rest of the Ford T-18. This will require some minor machining (hole drilling and tapping, hole plugging), but you'll have a WR T-18 that will bolt to your D20. The Ford T-18 input shaft is shorter than the Jeep shaft, so get a bellhousing from a Jeep with a T-150 or T-18, and that will adapt the Ford case and input shaft to the 258. This will make the length shorter by about an inch, but that's a good thing, giving you a slightly longer rear drive shaft.

    I don't see how the D20 is preventing you from using Toyota axles. Just get the right driveshaft made, and you can put in any axles you want.
     
    Last edited: Apr 6, 2011
  4. Apr 6, 2011
    ncgamedog

    ncgamedog New Member

    Charlotte, NC
    Joined:
    Mar 31, 2011
    Messages:
    24
    Good info guys! thanks!

    I was aware of the CR tranny :( And honestly I don't mind the 4:1 first if I could just pick up some t-case reduction. After having an SM465/203/205 doubler in my old blazer and an R151F turbo tranny (4:1 first) in my toy with a toy doubler sporting 4.7:1 gears in the back case, I have realized that for east coast wheeling I don't need a super low first gear. The granny in the blazer was actually annoying at times b/c I needed something in between, and well....the Toyota was just stupid low.

    I have nothing against the little Dana 20, I know they are plenty stout for my application especially. I guess, more than anything, I'm just not familiar with them. I thought that you couldn't twin stick them? and I was not aware of a reduction gear set for it. I bet it cost twice what a 4.7:1 gear set for a toy case cost. I have no problem with a hybrid drive shaft, but I just like the flanged toy shafts, they are self contained and toy joints are stronger than 1350's. So it'd be nice to be able to run the toy shafts but not required for sure.

    In reality, its looking like I will just run what I have. I would be interested in doing the Ford T-18 swap at some point though. So it sounds like the only mod to the Ford tranny is just getting the 20 onto the back of it? The T-150 bell housing takes care of the front end. Will the clutch mechanism/bell crank still work thats on the jeep now? Is there a write-up somewhere that outlines specifically what machine work needs to be done? link?

    Thank you again!
     
    Last edited: Apr 6, 2011
  5. Apr 6, 2011
    ncgamedog

    ncgamedog New Member

    Charlotte, NC
    Joined:
    Mar 31, 2011
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    24
    UM yeah OMG $1000 bucks for 3:1 gears????? I just saw that on AA's site. I was half kidding when I said they'd be double the toy case, but haha wow!

    Anyone wanna buy a nice 75 cj? lol

    UPDATE: So after even more digging, the final verdict is the trans and t-case are def staying (for now). I will do the Ford T-18 swap in stage 2 of the build. I contacted Jess at High Angle and he will make output flanges for the d20. I just need to know if my 20 is either 10 or 26 spline. I know its as simple as popping the yolk off but I'm 150 miles from my jeep. Does anyone know what it "should" be based on the year???

    Wish I had $800 right now, there is a rebuilt Ford T-18 already adapted to a twin stick d300 near me for sale.
     
    Last edited: Apr 6, 2011
  6. Apr 6, 2011
    Ghetto Fab.

    Ghetto Fab. Member

    Atascadero, Ca.
    Joined:
    Jan 13, 2005
    Messages:
    512
    My 75 had 10 spline outputs, fwiw.

    I think I paid less than $600 for my set of gears. I'm assuming that AA is just selling the Tera-low gears. Look around for other people selling Tera-low gear sets and you may be able to find them cheaper.

    Kevo
     
  7. Apr 7, 2011
    roadhog304

    roadhog304 Member

    Leon Kansas
    Joined:
    Dec 25, 2007
    Messages:
    291
    $800 in my opinion is a good price for a t18 dana 300. I paid alot more thaan that to get a t18 and a 300 but i went and found a scout dana 300.
     
  8. Apr 7, 2011
    ncgamedog

    ncgamedog New Member

    Charlotte, NC
    Joined:
    Mar 31, 2011
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    hmmmm so will an IH "texas pattern" 300 simply bolt up to the tranny that I have? Or would it require an output shaft change?
     
  9. Apr 7, 2011
    ncgamedog

    ncgamedog New Member

    Charlotte, NC
    Joined:
    Mar 31, 2011
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    Oh yeah Def a good price...I just dont have the cash right now.
     
  10. Apr 7, 2011
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
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    12,529
    It will bolt up, that's why they are sought after. Make sure you get the 6 spline input gear with it. Those can be harder to find than the transfer case.
     
  11. Jun 7, 2011
    CJ-X

    CJ-X Member

    Ohio
    Joined:
    Aug 6, 2006
    Messages:
    816
    The T-18 that was in my 75 had a 1" spacer that enabled the fitting of the dana20 transfer case to it.
     
    Last edited: Jun 7, 2011
  12. Jun 7, 2011
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
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    As per forum rules please email or pm the person about your for sale items classifieds belong in classifieds, not tech
     
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