When is a T-98 Not a T-98?


IHC in the early to mid-fifties.

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Post Wed Aug 14, 2019 10:11 am

When is a T-98 Not a T-98?

Answer: when it's a T-18. It seems not only finding a T-98 is difficult but when you do it probably isn't. There is a boat load of Warner four speeds out there with T-98 embossed on the top and side that are actually T-18 tranny's. I drove 250 miles yesterday one way to a junkyard in Colorado that has nothing but IH parts and trucks. They had a shed full of transmissions marked T-98 though most of them weren't. The night before I left I luckily came cross Novack's site and their information on identifying a T-98 which is to pull the cover and count the the teeth on the reverse / Lo gear which should be 43, most T-18's are 39 and to count the spur cut gear on the cluster which should be 17 . Also the diameter on the input shaft for the pilot bearing is a little smaller on a 98 as opposed to an 18. We pulled a bunch out of the shed and opened them up until we finally came up with one that was the real McCoy. I figured I'd post this here so it might help someone else if they are wanting to do the same swap. Beware of all the T-18's out there that are marked T-98.
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Post Wed Aug 14, 2019 10:18 am

Re: When is a T-98 Not a T-98?

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Post Wed Aug 14, 2019 12:20 pm

Re: When is a T-98 Not a T-98?

interesting, thanks for the info, is a T-18 shift pattern the same too? as reverse up by 3rd?

Sorry I didn't return your phone call, lots of stuff going on at the time you called,

Glad you found one,
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Post Wed Aug 14, 2019 12:26 pm

Re: When is a T-98 Not a T-98?

So, other than the pilot shaft size, what is the problem?
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Post Wed Aug 14, 2019 2:28 pm

Re: When is a T-98 Not a T-98?

bedrockjon wrote:interesting, thanks for the info, is a T-18 shift pattern the same too? as reverse up by 3rd?

Sorry I didn't return your phone call, lots of stuff going on at the time you called,

Glad you found one,


Not a problem, I figured you were swamped and my call was real last minute.

As far as I know the shift pattern is the same.
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Post Wed Aug 14, 2019 2:46 pm

Re: When is a T-98 Not a T-98?

nikkinutshop wrote:So, other than the pilot shaft size, what is the problem?


They use identical cases and I brought a template I made so I know it will bolt up. I suppose the shaft could be turned down or possibly a bearing with the right size ID and OD Could be found. I did notice that the front bearing retainer on some of the 18's that carries the throw out bearing was shorter and that the bearing retainer for the 98 and the 18 didn't interchange, an 18 retainer would have to have the back side milled out to fit a 98 case. Compound low is lower in the 98 than the 18, that's why the early CJ5 Jeep crowd goes nuts for them because they make good crawlers. For the way I use my truck I'm happy to have that advantage as well. The last difference is the 98 uses roller bearings on the cluster and the 18 uses a bushing. The juries out as to which is better.
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Post Wed Aug 14, 2019 3:13 pm

Re: When is a T-98 Not a T-98?

Thanks.
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