differences between T18 and T98

Discussion in 'General IH Tech' started by Brendan, Aug 1, 2003.

  1. Brendan

    Brendan Farmall Cub

    Can someone fill me in on exactly what the differences are between these two transmissions? I have heard many different things, from they are the same thing with a different number to different bearing sizes. Who's got the facts?
  2. Wheeled Scout

    Wheeled Scout Binder Driver

    The most significant difference is the bearing used for second gear, verse a bushing on the T18 second. Thus the main shaft's are not swappable. A majority of the cases are swappable, and a few of the other parts, possibly even the cluster gear.

  3. Brendan

    Brendan Farmall Cub

    How do they compare strength-wise? The bearing vs. bushing sounds like a point in favor of the t98. I'm watching for a t19 wide, like every one else. Is there any point keeping my eye out for a t-18?
  4. Wheeled Scout

    Wheeled Scout Binder Driver

    No point in looking for the T18 wide, pretty much nonexistent with the long IH input shaft. Some say the T98 is a better tranny because of the bearing, some say there are oiling issues with the T98 main shaft. I'd rather have a bearing over a bushing. The T98 also has a slightly lower first at 6.4:1. Also the majority of the T98's are 10 spline two wheel drive trannies, IH only used the 10 spline variety. I just so happen to have a T98 from a jeep that is 6 spline output with D20 adapter, and I have an IH T98 input shaft. I'd love to get rid of it, but the shipping to NE would kill the price.

  5. harleykeith2003

    harleykeith2003 Binder Driver


    I pulled 1 out of a 70 scout 800 and heard about a couple others coming out of 800s
  6. Brendan

    Brendan Farmall Cub

    The t98 in my 68 800 is a close ratio, I'm pretty sure. I only drove it under it's own power for about 50 yards. I really want the granny gear because i'm not going to run low axle gears to keep it highway friendly.

    In what trucks was the t98 2wd used? Would that be a good source for the 6.xx fist gear?
  7. Mechanos

    Mechanos Binder Driver

    Might be a good source for 6.xx GEAR, but you will not be able to use the 2WD tranny in a married-case setup in a 4WD. The 2WD case is drilled for a bearing retainer and the 4WD case is drilled differently for the t-case adapter/bearing retainer. You could redrill the 2WD case for the adapter, but then there is the mainshaft situation. The 2WD tranny uses a 10 spline mainshaft and the 4WD tranny uses a 6 spline mainshaft. You could, however, find a 2WD wide box and swap the wide gears and cluster gear from it into the 4WD case and get your 4WD wide ratio tranny with the right mainshaft that way.....
  8. Allan E

    Allan E Lives in an IH Dealership


    The 68 800 used a T18. It's often confusing, because the top cover says T98.

    All pickups and travelalls with 4 speeds used T98 transmissions until the T19 took its place in the early 70s. All were wide ratio. Likewise, the scouts all had T18s until the same time, and all were close ratio. You can actually tell which transmission you have by the gearing.

    I agree with TORC, the way to do this is find a jeep T98 and use the IH gearset if it's possible. I don't know anybody who's tried. In fact, it wasn't until recently that I even knew Jeep used T98 transmissions, and that lit the light. Now I just have to find out where they were used, and how hard it would be to do the conversions with two good donor transmissions.
  9. Wheeled Scout

    Wheeled Scout Binder Driver

    Jeep used the T98's in the J-trucks, the swap would be easy, just use the main shaft from the J-truck, use the rest of the parts from the IH T98, and redrill the case for the D20 adapter. Also if you're lucky and have a T18 top cover then you can use that for the reverse light.

  10. Stephen Tate

    Stephen Tate Farmall Cub

    Joe D.- What is the input shaft like on that jeep trans.(shaft length and spline count)
    I was wonderong if it would be the same as a 4cyl 800 t-98 shaft. That would be an easy swap for me (got a t-18 close w/t-98 top plate) If not, to get a wide I still have to find a Ford t-18 wide and swap the gots into my IH case. Just being wishful...
  11. Wheeled Scout

    Wheeled Scout Binder Driver

    It's about as long as an IH input from a truck, but is smaller in diameter, and uses an odd bearing retainer. I would bet you could use a Ford T98 input, which is short in length, good sized diameter, and I think 10 spline.
  12. Mechanos

    Mechanos Binder Driver

    I don't know for sure since I've never been inside of a T-98, but the T-19 conversion goes something like this:

    T-19 close to wide swap

    I did this about a year ago but I still remember a lot of the little nuances (the pics help too :D) so feel free to ask questions if you have any and I'll try to answer them.
  13. Brendan

    Brendan Farmall Cub

    I was hoping this would turn into an informative thread.

    Thanks for the info. I can add another jeep source for the t98---the FC trucks also used them. If you find one of these SAVE the shifter. They use a really bizzare shifter that wraps around the side of the case and runs forward a foot before it connects to the stick. They are hard to find and worth a fair bit of money to the FCrazies because it's the only way to get a four speed into the truck.
  14. David Lang

    David Lang High Wheeler

    so it sounds like it's 6 gears to convert from close to wide (the 3 on the mainshaft for 1st, 2nd and 3rd and the corresponding gears on the countershaft)

    are these gears available as parts from somewhere?

    given the price that people are asking for used wide ratio transmissions it may actually be cheaper to get teh gears new.
  15. Mike N

    Mike N Farmall Cub


    The gears aren't available.
  16. Wheeled Scout

    Wheeled Scout Binder Driver

    Re: Bummer

    Should be, just need to find a good tranny shop, try Boarder Parts and see what they have to say.

    But you're better off find a complete donor tranny.
  17. Mechanos

    Mechanos Binder Driver

    Can't speak for the T98, but for the T-19 it's five gears. Main drive gear, 2nd, 3rd, 4th and the cluster gear (looks like 4 gears but it's one solid piece). As for not being available, I bought a brand spankin' new reverse idler gear when I did the swap to replace the pitted gear. If that one was available, the others should be too I would think.
  18. Mike N

    Mike N Farmall Cub

    Border Parts says they aren't available?

    Wheeled Scout - Do you have a source?
  19. Wheeled Scout

    Wheeled Scout Binder Driver

    Yeah a complete tranny :D

    I also have another T98 that is 2wd and disassembled.

    What exactly are you looking for?
  20. David Lang

    David Lang High Wheeler

    there are several people who have been looking for a T-19 wide transmission, if replacing 5 gears can switch a close to a wide there are a number of us who would consider it (I would need to get an overdrive unit before I would use the wide, but I start gathering the pieces early :))

    if a doner transmission is available in your area that's fine, but I have been looking at buying a transmission for $500 and have it shipped across 3 states to get to me, that's not going to be cheap and buying the gears and converting an existing transmission (or buying a T-19 locally to experiment with :)) is a whole lot easier

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