T90 Part Confusion

Hi Everyone,
Am new here and was hoping that someone could shed some light on my delima?
I was given this CJ3 from a family friend that has since passed. My promise to him was to get it running & drive again though before this could happen... he passed away.
So this has become more important to me now.
The CJ is somewhat of a "Frankenstein" of a build... CJ5 frame, 48' Tub, 48' axles, Chev. S-10 V6
Was stored in the rain for 20+ years in his backyard so engine & trans was full of rain water..!
Pulled engine & trans. out... rebuilt engine...now the T90 & DANA 18...
The T90 was absolute "garbage" case included as it was cobbled together with some crude adapter arrangement & full of water.
Purchased another T90 ( was told it came from a International 800..?
Here is where it gets weird...
I needed to change out the Input shaft to the longer one, ie., GM ( Omix # 18880.09 )
Pull the Main-shaft assembly out, replace the Countershaft with the correct tooth count for a 18T Input.
Countershaft ( Omix # 18880.22 )
I noticed there are two different needle bearing callouts for the Input to Main-shaft connection.
One bearing diameter = 0.156" Other = 0.218"
Here is the weird:
GM shaft measures 1.205" bore diameter versus the original shaft bore at 1.218"
I measured the old input shaft ( GM shaft as well from the junk trans ) = 1.205" also
If one used the 0.218" bearings would net a bore diameter = 0.769" ( old Main-shaft measures = 0.760" )
Using this combination would yield a 0.009" loose fit..?
Using the 0.218" bearings would yield a bore diameter = 0.893"
The diameter of the purchased transmission main-shaft = 0.905" ( ??? )
I am curious of what T90..? Utilizes the Main-shaft diameter of 0.905" versus the 0.760" I have on all T90's I have. I need to use the GM style Input shaft as I have already designed and machined up the correct adapter to mate the T90 back onto the S-10 v6 motor.
Sorry for all the wording....anyone out there that may have an clue to my delima?
I have ordered the standard Main-shaft but really did not want to transfer all the parts to another shaft.
Your help would be appreciated..!

 

The pickups and wagons among a few others used the bigger input shaft behind a straight 6 engine
Your combo sounds a lot like mine and is common.

Adapting the Chevrolet & GM Standard Shift Bellhousings to the Jeep T90 Transmission

20181111_215538 by Joe with a jeep, on Flickr

 

As I look at your picture ( sorry don't have any of my own yet )
I first noticed the bearing retainer on yours is the same as mine... Hard to locate this a mine is cracked. I thought someone had did some lathe work but it is "stock".
I like the oil filler pipe... You got to keep that...ha ha ha
I have two of these T90's...both with markings, T90A-1
First ( out of the jeep ) was absolute junk...even the case is NG.
Jeep was stored for many years outside...water got into the engine ( I rebuilt ) Trans was full of sludge & water...destroyed all gears, shafts, bearings.
Purchased another trans ( T90A-1 ) was told it came from a International 800?
Since the original trans had the GM Input Shaft...I purchased another and was going to only change out the Input Shaft on the 2nd trans when all the fit issues come up.
Problem I have identified was the fact that ALL T90's have a bearing diameter = 0.760" at the Main-shaft to Input Shaft.
The Main-shaft "assembly" I was going to use has a shaft diameter = 0.905" ???
Tried both options of needle bearings on the input shaft .
Bearings used:
0.156" gives a I.D. 0.893 ( 0.012" too small using the main-shaft from the trans I purchased)
0.218" gives a I.D. 0.769" ( 0.009" oversize of the 0.760" old main-shaft diameter
Am I missing something here?
Do have another main-shaft on order with the 0.760" diameter...or option two would be to centerless grind the bearing journal from .905" down the 0.012".
Just curious as to what the main-shaft is actually from???? Or I missed something

 

IH had some different angles and tooth counts on some of the gears for their applications.
So an IH T90 (IH called it a T-14?) may not be the same as a Jeep T90.
One must be cautious

 

Is it possible that this transmission I just purchased as a " T90 " may be the T90 case and use the T14 Main-Shaft & Counter-Shaft..?
I just found this assembly on Ebay ( Main-shaft ) with all the gears still on it....looks to be the same other than maybe who ever built this did change the 1st-reverse gear ( T90 Straight cut gear …. T14 seems to have helical cut )..???

 

Jeep T-14 gears won't fit in a T-90 case. A Jeep T-14 is very different from a Jeep T-90. Calling this transmission a T-14 will be sure to generate significant confusion.

Jeep T-90s are rather plentiful. You can buy a Jeep T-90 with all new gears, and adapted to a GM bell, complete and ready to go to. Most of the Jeep T-90 parts are available today as aftermarket reproductions.

I would steer clear of anything from IHC as it will have double secret oddball status in the automotive world. JMO. If you can make this transmission work, great, but I predict you will have to work it out on your own. Jeep T-90s are not that scarce ... and you are adapting a the 60 degree V6, right? Again, something different. I'm sure it's been done, but you'll have an easier time with the 90 degree engines that can use the standard Chevy bellhousing.

 

..hence the confusion when mixing IH and Jeep.......
.....the designators are different....

 

Just a heads-up, but the Omix gears don't seem to be near the quality of USA made parts. There are several versions of Jeep T-90's; T-90a, T-90c, and T90j. The first two have a short input shaft used behind the 134 four cylinder engines, but differ in the 1st gear ratios. The T-90j was used in Jeep trucks and wagons with the inline 6 engines has a longer input shaft, but shares the gear ratios with the T-90a. The longer truck input shaft (18 tooth) is commomly used with an aftermarket adapter plate to mate to a Chevy 90 degree bellhousing. The Chevy 60 degree bellhousing is likely different. Which S10 engine do you have, 2.8 or 4.3 liter? The 4.3 is a 90 degree engine just like the V8 Chevys. The 4.3 was used after 1988 model years. The 2.8 is a 60 degree engine that may cause headaches trying to mate to the T90.
It is also likely that your rusty T90 transmission had custom machined parts to enable it mate to the the engine you have. You would be best to stick with Jeep specific T90's because of parts availability. The IH and some Studebaker T90's had their unique designs that made them incompatible as far as parts swapping, as mentioned in previous posts.
-Donny

 

This Jeep is a Frankenstein build... Not my way of doing things, but none the less...need to get it right & running.
The engine is a 2.8L v6...S-10 It was "shade tree" built as for mounting the trans to the S-10 bellhousing using two 1" steel plates cut with a torch I think.
There was no regard to alignment from crank to trans...hence: COMPLETE trans failure...then add rain water for 20 years.
I designed up & machined up a correct adapter in my shop to correct the mounting & alignment.
Engine was junk ( full of water & seized )… Tore down...rebuilt.
Transfer case seems OK for now.
As for the T90...This why I went ahead and ordered the correct Main-shaft to replace the IH shaft.
I could take the IH main-shaft and put in my centerless grinder... would still need to take apart...either way.
Oh...did I forget...frame is cracked in about 5 places... one place bad.... Seems he installed a CJ5 frame ( shortened ) to fit.
Instead of Z-cutting the frame rails when shortening...just a straight cross cut with no plates even...broke at this weld as well.
Will break out the Stick to fix these.
Next will be to look at the axles...center & brakes.... electrical looks like someone walked by...opened the hood and threw a box of old wire at it... Another day..
Parts still looking for:
Front Driveshaft … MIA
E'Brake Assembly ( Drum type ) and all to put on the D18..? Also MIA
Other than this... Getting there....
As I figure out how to add pics....
Thanks..!

 

Ran into a " Unknown " and I could use your help here.
I ordered a replacement Clutch Disc since the old one was oil soaked.
It came in today and realized it won't fit..?
What I ordered was from Quadratec, p/n: 16905.02 ( 67-71 Jeep CJ )
Spec's: 9.20" Diameter, 15/16" Shaft, 10-Spline
I have installed the Omix-Ada Input-shaft p/n: 18880.09
Spec's: 1-1/8" Shaft, 10-Spline
Now I see it won't work since most descriptions don't specify the Input-shaft sizes.
I need to stay in the 9.20" or 9-1/4" Disc diameters as the Engine layout dictates this with Flywheel & Pressure-plate.
I have looked at the existing Clutch-disc for ANY identifying marks & numbers...there are none.
Does anyone know what this old disc came from???

Option # 2
I have thought of this idea....
Since the old clutch disc is only oil soaked and very little wear... I soaked in brake cleaner & lightly torched it several times to soak off & burn the oil off.
Has anyone tried this..???

Option # 3
Would be to use the "Jeep " 8-1/2" clutch plate..?

Thanks,

George

 

Really striking out here and I know the part exists as I have the old one...
I contacted Quadratec to return this one I ordered and to discuss what might be the correct one to re-order.
They can only go by application.....which I can not give them anything as it is a Frankenstien setup to begin with.
You are correct in the application using the "GM" shaft...
I wished I knew you had "shelf parts" available before I ordered pretty much all the internals as the original T90 was absolute junk....including the case ( cracked ). I purchased another T90 with the idea of cleaning up...paint...and stick it in.
problem....Did not have the correct Input shaft in it is why I planned to only change out the Input Shaft....
That is when I noticed the bearing diameter ( main-shaft ) was larger @ 0.905"...Not the 0.760"....so nothing fit up using either the "small" or "large" needle bearings in the end of the Input shaft would fit.... Hence....I purchased a replacement Main-shaft...planning to take all the parts off the 2nd T90 shaft and put them on the new main-shaft to get a fit up....
The Clutch Plate is just I guess another step in getting this back together.
T90's are by far the easiest to rebuild....I have done a T98 for my truck....and did race prepping years ago for the Muncie 22's for a local speed shop
This one is kicking my tail
Thanks,

George

 

Just an Update:
Learned my lesson...
If you are planning to "marry" parts from one transmission to another to get a working " Jeep " T90 trans....
Make sure the "Donor" trans is NOT a International T90...!!!!!!!
They look the same....They are laid out the same..... They are NOT the same....!!!!

The ONLY parts I see that "could" be used from the International T90 in this case....To Build a " Jeep " T90.
Hub Syncronizer ( If you keep the springs & Dogs ) ( Dogs are wider & Different Springs ) Syncro Rings look to be the same, but don't trust.
Side Note: I believe Novak carries these assemblies with the wider Syncro-Dogs, Hub, Springs, and Syncro-Rings.
Gear, Sliding, 1st-Reverse
Bearings, ( 88 Count ) + ALL Spacers for the Counter-Shaft..... NOT the Counter-Shaft, ( Tooth Count Different @ the Input gear Count of 16T )
Bearing, Main-shaft-Rear
Gear, Reverse Idler + Shaft ( Same Tooth Count )
Case-Main, ( This one does not have the drilled holes in the front of the case to install the "Oiler" Rail )

The Retro-Fitting of a Input-shaft ( GM Style ) into a former T90 Transmission is very simple as it does not effect any internal parts ( Gears ) UNLESS you are
converting an EXISTING Input-shaft with the 16-Tooth count to the GM style ( 18-Tooth ). Also... The Front Retainer Bearing Housing ( Front Input-Shaft Seal
needs to be changed as well if the shaft being replaced is of the 15/16" diameter 10-Spline, the GM Style is of 1-1/8" Diameter. ) The Front Bearing Retainer Housing may need to be replaced to accommodate your existing Clutch & Throw-out Bearing arrangement.

What started this nightmare of a project.... The original T90 from the Jeep was junk... Upon taking apart & cleaning up the parts, I found a crack in the case.
I thought, " Be cheaper to find another T90 ".
I had to change out the Input-Shaft to the GM Style is where it ALL become a nightmare...!!!

As mentioned earlier in this thread, " Stay Away From The " IH " T90's
It was too late…. " IH " =

 

I have a genuine OEM NOS genuine Borg Beck driven disk that is available.
In a Willy Motors box from the early 60's.
PM me if your interested.
It is a 1-1/8" by ten spline 9-1/4" diameter driven disk and was original to Jeep SW and PU with 226-I 6 engines.

 

Would be maybe interested in that Clutch Disc...yes sir.
Thanks.
BTW.... This T90 has been a disaster,.... BUT.... another learning.
Thanks,
George

 

Here's pic of the 1-18" ten spline x 9-1/4" NOS Borg Beck disk.....

 

Looks like the critter...
Would you be willing to sale & ship?
And $$ …?

Thanks,
George

 

George, I sent you a PM ...

 

Quite the rabbit hole.

Shame about the T90. Few on the forum would have agreed to rebuilding either a 60 degree V6 or a trashed/poorly adapted T90 both of which had been filled with water. You may well be best served to ditch all that you have done so far and start from scratch. The guys here can steer you in the right direction. I know your sunk costs are significant and might be justified if the end result was a good, functional one. But that's a big if.

One certainty with the old jeeps- you will pay for your "education". Done now or later, you'll end up paying.

 

Oh how true.... lesson learned here and then some.
What started out as a simple deal...turned ugly.
I have now all the correct parts on the bench now.
Using the IH case as it was the ONLY usable main-case....all the running parts are now new, ( Jeep Type T90 ).
Still awaiting the 2nd Gear & clutch Hub Assembly to finish.
With any project there is ALWAYS that unknown....what direction...what option...or what part.
My 1958 Ford 4whl Truck was this.... My restored Flat Bottom Race Boat was no exception.
Come to think of it.... Definition of B-O-A-T... Break Out Another Thousand...
But heck...If it was simple...EVERYONE would have one...hence the "Belly-Button" car....
The challenge is half the fun in my book.....The fun of driving it the other half..... The Pride I built it is priceless.

Appreciate & Thanks to all the support!!!
George