Transfer Case Upgrades and Modifications

oldtime, thanks for all the information on the TC's over the years. I'm just now taking my T-90 and transfer case out from behind the Dauntless. I also have the Dualmatic overdrive attached. Its a rear shift OD. I have been thinking about doing the TL kit while I have it apart. Now you have me thinking about doing the tapered bearings as well. Who would I send my case to have machined for the tapered bearing ? Is there a pre packaged set (shaft-bearings) that one can buy or would the shop know what to use? Excuse my ignorance, I only just rebuilt my first Dana 18 a year ago. It was easier than I thought, but this is new ground for me. Thanks

Thank you Sir. I will contact Mcruff and ask him. I just broke my T90 down today. (sick of the smell of diesel)  and will get to taking the TC appart tomorrow for a good bath in the diesel tank and cleaning. Its a small hole 18, but I have a nice 20 in the former sugar house, that I was thinking of using my 18 guts in. Not sure how that would upset my overdrive yet. The CJ2a (Jalopy)  I got from Nate is now sitting on a flanged 44 offset and soon a disc front 30, but they are geared as 373 right now. I will either have to drop my gearing in both axles, or go with a Terra low in TC. I'm thinking for now, to re-gear my axles and just use the OD on paved roads. I'm also thinking that the lower geared input shaft and cluster gear would be a good way to go, now that I have the T90 apart. Are those the only two parts to change on the T90, the input shaft and cluster? Or is there more hidden knowledge that is in your wisdom.   Yes, I said former sugar house, now its a parts out building.

oldtime the engine in it is a Dauntless 225. Was thinking at some point of putting in a 231 even fire, but that's down the road when I do a full frame off build, maybe this winter or next. Probably next year as I also want to finish up my CJ6 build. This one has kind of jumped in front of that CJ6 build as I have been challenged to get the Jalopy ready for the June New Hampshire trail ride. The Jalopy was a favorite at that one. So mechanically, just trying to get this set up for that right now. I was also thinking 488's for gears and may make that happen prior to June, but not sure as costs may restrain me from doing that right now. Been out of work for over two years and money is sometimes a little slim around here. I was also thing, while I have the T90 apart, of doing the lower first gear on it. From what I can tell (correct me if I'm wrong) I can purchase the low gear input shaft and cluster gear, to do this. Is that correct or is there more to it than just those two items ?

Edited by masscj2a - 17 Apr. 2019 at 3:24pm

For what it's worth... Our Willys runs a 225, t18 and "super 18" transfer case with Rock Eater 4.86 gears. It also has 3.73s in the rears on 35 inch Boggers. It's getting regeared to at least 4.27 if not 4.88. Too much downshifting on hills with 3.73s. No over drive needed.

Edited by Y2GREY - 18 Apr. 2019 at 11:47am

Well I sourced a Ford T18, 2WD version. It also came with an empty Jeep T18 case and main shaft, along with the T98 rear adapter and adapter seal bushing. The T98 adapter only fits the Jeep case. I have already swapped over the gears to the Jeep main shaft. Well except the three poppet balls and spring on the clutch hub. (I need another set of hands) Have them held down right now with a large radiator hose clamp. I have ordered a AA bell housing adapter that adapts both the Ford and Jeep cases along with others.  The same person also gave me the big hole Dana 18, but it is a bare housing. I have my Dana 18 small hole parts and pieces cleaned up, but waiting for the Novak rebuild kit to come in. Still not sure if the Dual matic will work in the end, but not worried to much about that with the current 373 ratio axles. But at least now with the 632 first gear, it gets me in the ball park with 34 inch tires. Thanks again for this article. It has shed a lot of light on the subject for a lot of people.

Edited by masscj2a - 05 May 2019 at 1:19pm

Hey Oldtime, just wanted to say thanks for all of the valuable info in this post.  I'm planning on building a large hole 18 with the TL kit and mount it up to a T90C.  It's not going to be a fast, but I plan to frequent this post, among others, as I'm going through the mod.

I case you never got a response, NO, the terra low overdrive bowl gear is not compatible with the planetary gear pitch in the Dual Matic spider blank.

Is the terra low overdrive bowl gear  compatible with the Husky OD?  I have one for a 29/ 6 gear set up.