T-18 transfer case fitment

Does anyone know if a Dana 18 t-case from a 61 pickup(L-226)will fit a 69 CJ5 that came with an 18 also. I think the truck T-90 trans has a longer input shaft but what about the T case? The CJ is a F-head. Thanks

 

The t-90 J(?) is the transmission with the longer input shaft for trucks and what you use for the 225 to t-90 conversion. The D18 should be the same as all the others, but I could and might be wrong.

 

The chart on the Novak site will tell you what used which transfer case - http://www.novak-adapt.com/knowledge/transfer_case_gears_grid.htm

The third row indicates the D18 (not T-18, that's a transmission) will fit F134 CJs through 1971. Measure the intermediate shaft diameter and look at the numbers on the gears to be sure.

Welcome from Boston!

 

Yes, but if we are talking about CJ-5s, and 226 Utility Truck/Wagon, the only different input gear (10 spline) is for the CJ-5 V6, and the OP says he wants to match a CJ with a 134 (6 spline).

 

You can easily measure the intermediate shaft diameter and distinguish the 26 tooth from the 29 tooth case. And the chart claims that the 26 tooth case was never used for the CJ-5 or the 226 Wagon/Truck. The only way a '69 Jeep or a Utility would get the earlier case is if it were swapped in - unless the chart is wrong. But it's been posted like this for more than a decade, so I presume it's fairly well vetted.

Maybe you are making this more complicated than it is?

 

Well, what does the parts book say? '60 is contemporary with the 3B, which apparently got the 26 tooth case. Does your TC have a tag? If it's missing a tag, then it's been out of the Jeep at least once before 1980.

 

billybones,
The transfer cases could possibly have different output yokes or companion flange.
otherwise they should be identical.

Glenn,
DANA MODEL 18 TRANSFER CASE PROGRESSION

Like all Jeep components the infamous Dana model 18 underwent a continual progression of changes.
The earliest changes occurred even before MB / GPW production.
After MB / GPW the intermediate shaft diameter was changed from 3/4" diameter to 1-1/8" for increased strength and durability.
Also the MB / GPW's meager 1.97 to 1 ratio was changed to 2.43 to 1 ratio for the CJ universals.
The 2.43 ratio D18 is a fairly good transfer case and it's plenty strong behind typical early Jeep engines.

The Dana 18 was changed yet again in mid year 1954-1/2.
This progression changed the ratio from 2.43 to a 2.46 to 1 ratio.
Why bother ?
That was Dana Spicer first attempt to quite down the model 18 transfer case.
The gear teeth were re-cut finer and at a slightly different pitch.
The intermediate shaft once again was then increased to 1-1/4" diameter.
The roller bearing count was also increased and the roller cage was eliminated.
The 2.46 to 1 ratio small hole version (3-5/32" index bore) is the time proven standard for the D18.
That implies that this particular small hole 2.46 ratio transfer case assembly was used for the greatest duration of time. (1954-1/2 to 1971)

In 1962 the silent type transfer case was finally perfected and it is commonly known as the Dana model 20. (D20)

All D18's built before 1965 have 3-5/32" transmission index bore.
The 2.46 ratio D18 was once again modified in 1965 for use with the more powerful Dauntless engines.
This last progression of the D18 is commonly called the big hole D18.
The big hole D18 utilizes the stronger and slightly heavier D20 case with it's inherent index bore @ 4".
The big hole D18 gears sets remained the same as the 2.46 ratio small hole D18's.
The big hole D18 front bearing cap was changed to a single stick configuration.
It is the strongest of the D18 transfer cases.

One cannot simply swap the gears between 2.43 ratio and 2.46 ratio D-18's unless all of the gears are swapped.
However one could swap the complete 2.43 gear set into a 2.46 case and in order to utilize the 1-1/4" intermediate shaft.
D-18's were never built as 2.43 ratio with 1-1/4" intermediate shaft from the factory.
Other transfer case parts swap combinations are also practicable.
D20 cases can be used for many drivetrain applications intermixed with 2.43 or 2.46 ratio gear sets.
The ultimate D18 entails the stronger big hole case with 2.46 ratio or aftermarket ratio components plus the use of a twin stick front bearing cap.

 

This is all very interesting, but maybe we should focus on the OP's question.

To the OP, I expect that if the transmission gears (the bull gears on the transmission main shaft) match, the two transfer cases should interchange. Each bull gear will have a part number that tells you what the tooth count is. This is the "Drive Gear" column on the Novak chart. That should be enough to answer your question.

Ken, if this is not correct, please comment.

 

Note:
All 2.43 ratio transfer cases (unless modified) have 1-1/8" intermediate shaft.
All 2.46 ratio transfer cases (unless modified) have 1-1/4" intermediate shaft.

All 2.43 ratio use a 26 tooth transmission main shaft gear (T.C.input gear)
All 2.46 ratio use a 29 tooth transmission main shaft gear (T.C.input gear)

billybones states that he has a 1969 CJ-5 with F-134.
The stock transfer case for that application is the 2.46 ratio small hole (3-5/32" index bore) D18.
The 1961 P.U. also utilized a 2.46 ratio small hole D18.
So the basic transfer case and transfer case gearing is identicle between these two jeeps.

I'll take a look at the books to see what if any differences he will encounter.
Likely the speedometer gears are different and possibly the shifters and rear output yoke.
If I remember I'll check the 1961 pickup specifications.

By the way I may be interested in the (two) 1961 speedometer gears if they do not fit your needs.

 

The Novak chart also lists all the transmission main shaft gears( the transfer case input gears). It is critical that they match the transfer case. There are six(internal splines) by 26 or 29 (external splines) that have a different pitch. Ie. an 18-8-19 is different from an 18-8-46 but at a glance look the same. The gears were cut at either 17.5 degrees and at 20 degrees. They will bolt up and run either way but will howl like you won't believe. Very discouraging to think you have the project buttoned up only to test drive it and have a screaming transfer case. With the bottom pan off the t-case you can visualize the number on the front output shaft gear and match it up on the chart. This can help eliminate the frustration. It is very helpful when one pulls a transfer case out of a vehicle that the gear be removed from the transmission and kept with the transfer case to eliminate the question of which gear goes with which case. As we go into the 8th decade of Jeeps, it is impossible to know what may have been done by a previous owner on the new to you Jeep.

 

Yeah, the Willy Pick Up parts list basically confirms what I already stated.

The speedometer gears could be set up 4.27 4.88 or 5.38.
Your 1969 CJ-5 is 3.73 or possibly 4.88.

The shifter levers are identical.

The 61 PU uses 18-8-23 transmission main shaft gear. (29 tooth x 6 spline)
The 69 CJ-5 uses 18-8-50 transmission main shaft gear. (29 tooth X 10 spline)