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Transfer Case Progression

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    Posted: 28 Aug. 2018 at 9:23pm
DANA  MODEL 18 TRANSFER CASE PROGRESSION

Like all Jeep components the famous Dana model 18 (D18) underwent a continous progression of changes. 
The very first transfer case changes occurred before mass production of the MB/GPW.
Bantam was concerned with where to place the transfer case outputs in relation to the axle carriers..
The early Bantam BRC transfer cases had LH outputs and LH differential carriers

In 1945 the intermediate shaft diameter was changed from 3/4"  to 1-1/8" for increased strength and durability.
Also the early military ratio of 1.97 to 1 was changed to 2.43 to 1 for all 1945 and later Jeeps.

The 2.43 ratio D18 was used from 1945-1954-1/2.
It is a very good transfer case and it's plenty strong behind  any Willys engine.
These Brown / Lipe units remained basically unchanged through CJ2A and CJ3A production.

In 1953 both front and rear output shafts and their associated nuts were changed.
A "Hug Lock" nut replaced the previous "Castlelated" nut. 
The Hug Lock nuts have less thread pitch and they also interchange with those on the axle pinions..

Shaft changes and A-980 vs 801367 nuts:

As the 1953 3B came into production the safety wiring of bearing cap bolts was done away with.

The D18 was changed yet again in mid year 1954-1/2.
This progression changed the ratio from 2.43 to the 2.46 to 1 ratio.
So why did they bother ? 
This was actually Dana Spicer's first attempt to quiet down the model 18 transfer case.
The gear teeth were re-cut finer and at a slightly increased pitch.
The intermediate shaft  was once again increased in size to 1-1/4" diameter.
The roller cage was eliminated and the needle count was increased to 48.

Here we see the  1-1/4" intermediate shaft and associated parts:


With this 2.46 ratio transfer case the rear output companion flange yoke was upgraded.
This upgrade from part # A 950 to # 807784  provides slightly increased propeller shaft angles without yoke binding.

Here we see the early shorter companion flange yoke next to the improved longer yoke:

The 2.46 ratio transfer case became the "time proven standard" concerning Jeep transfer cases.
That implies that  this transfer case was produced for the greatest duration of time. (1954-1/2 to 1971) 

In 1956 the CJ park brake operating lever was changed from the A-17254 to 915892. 
It went from 5-3/8" OAL to 7-11/32 OAL in order to accomidate the T98-A transmissions.

Here we see the longer park lever that was now required with CJ-5 and T98-A applications:


In 1963 the D18 received a small change concerning shift fork set screws. 
They went from # A 963 set screw having safety wire to the Allen head set screws.

Old type vs updated shift fork set screws:


"All"  D18 transfer cases built before 1966 model year have a 3-5/32" transmission index bore.
The 3-5/32" index bore indexes direct to the T90 mainshaft bearing (Fafnir 307 K)
There were no more 3-5/32 index bore cases built after the 1971 CJ's with  F-134 engines..

The D18 received a divergent factory change in late 1965. 
These D18's were specific  to CJ's with Dauntless 225 engines.
This case was upgraded to the 4" index bore casting that was previously developed by Dana Spicer.
This larger index bore allows for transmissions having larger mainshaft bearings than a T90 uses.

Here we see the Small hole vs the big hole indexing bores:

For clarity I will refer to the 2 case castings as either "big hole" or "small hole" and  certainly not as  D20 cases.. 
This last factory progression of the D18 is commonly called the "Big Hole D18".
This big hole D18 utilizes the stronger and slightly heavier casting with it's inherent 4" index bore. 
The big hole D18 gears sets remained the same as the previous 2.46 ratio small hole D18's.
However the factory big hole D18 front bearing cap was changed over to a single stick configuration.
The big hole D18 is certainly the strongest of the factory D18 transfer cases.

Stay tuned .....more to come.



Edited by oldtime - 05 Sep. 2018 at 12:21pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 29 Aug. 2018 at 8:38pm
DANA MODEL 20 TRANSFER CASE PROGRESSION

Although the D18  was improved; Dana Spicers 1954 attempt to silence the transfer case was a failure.
Just prior to the1962 model year the "silent type transfer case" was finally perfected.
It is commonly known as the Dana model 20. (D20).

This unit was an absolute ingenious re-design of the D18.
The new D20 was basically a re-configured D18.
And so It utilizes many of the very same parts as the ever famous D18.

The main difference between them being the very similar yet improved case casting.
This 4" index bore casting allows for additional transmissions having larger rear main shaft  bearings.
For clarity I refer to the basic case castings as either big hole or small hole and  certainly not as D20 nor D18 cases.
As an added benefit, the big hole also allows one to separate the transmission from the transfer case without removal of the mainshaft gear.

The mainshaft gear::


For ease of identification; "all" big hole cases have the addition of a second shift rail pocket exiting out the rear of the casting. 

Here we see the shift rail pocket on small hole vs the big hole case:

This additional shift rail pocket is required for use with D20 transfer case assemblies.
These big hole cases are a bit more stout than the small hole cases with no increase of overall space.
As a bonus the internal area specifically surrounding the intermediate gear was slightly increased.

The D20  was initially placed into the newly developed Gladiator and Wagoneer models.
At the time it evidently was deemed impractical to install the D20 into CJ models.
Willys Motors reasoning was likely influenced by the short wheel base and offset of the CJ's rear axle.
 
In 1972 AMC Jeep Corporation  lengthened the CJ to 84" and the D20 became the new standard for CJ's.
Jeep's Dana 20's Circa 1962-1979 were always geared with  the meager 2.03 ratio gear sets..

A few different designs for D20 front bearing caps were used on the various Jeep models..

The D20 front bearing cap shown here is designed to accept the "J" shifter assembly:


Several different shift lever assemblies were designed for various Jeep models.
Sadly all Jeep models used single stick control on the D20 transfer case.
This "J" shifter is most often considered to be the best of the single stick controls.


All early lube fill plug were on the LH end but that practice changed around 1972

Big hole cases without a LH fill plug vs  case with the LH fill plug:


Later big hole with the rear fill plug:

Beginning in 1970 mechanical type of "lever and tube" clutch control assemblies changed on CJ's to a cable control system
So many of the post 1970 big hole cases are no longer tapped to accept a clutch control pivot stud..

Pre 1970 -1972 big hole that is untapped for clutch control.



That said we still see some big hole cases being tapped to accept clutch control pivot studs way into the late 1970's 
Here we see a post 1976 case with a bolt plug in the pivot stud tap:


Beginning in 1980 the D 20 gave way to the D 300.


STAY TUNED.........



Edited by oldtime - 10 Oct. 2018 at 11:09am
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bob W Quote  Post ReplyReply Direct Link To This Post Posted: 29 Aug. 2018 at 8:46pm
Thanks for taking the time to compile and post this great information!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 64CJ5 Quote  Post ReplyReply Direct Link To This Post Posted: 29 Aug. 2018 at 9:51pm
Thanks for the information.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote willys54wagon Quote  Post ReplyReply Direct Link To This Post Posted: 29 Aug. 2018 at 11:28pm
according to this the d18 can be enlarged to the 4inch bore and better bearings:

Individuals that have 1-1/8" shaft transfer cases should know that their cases can be precision line bored to accept 1-1/4" intermediate shafts and their larger contingent of bearings, resulting in quieter operation and longer gear bore, shaft journal and needle bearing life. This is a service that Novak provides on request. Cost is $191.25. Contact us.

https://www.novak-adapt.com/knowledge/transfer-cases/model-18/

anyone done this? not cheap but worth it? maybe in a v-6 conversion?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 30 Aug. 2018 at 10:55am
Sorry the Imgur linked images are going crazy again.
I did not change a thing.
They just dissappeared on this forum but still show in my Imgur account.
I'll just leave it be for now and see if the pics re-surface.

I've just about had it with photo hosting.
Still have not recovered the pics from my Photobucket account.



Edited by oldtime - 30 Aug. 2018 at 10:57am
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 30 Aug. 2018 at 11:43am
Interchanging of Standard D18 / D20 Components

The big hole casting having left side fill plug was original for both the D18 and D20's.


This pic shows all internal parts that always interchange between D18 and D20  transfer cases. 
(except qty two # 14276 bearing cups that are not shown)


The D18 gear set consists of 4 gears total.
And the full set  includes the transmission mainshaft (output) gear.

Here we see the standard D18 4 gear set of 2.46 ratio:

The complete D20 gear set consist of  5 gears.
So obviously when building a D20 in lieu of D18 it will need the additional (5th) output gear.

Here we see the 5 gear set at 2.03 ratio:


One cannot simply swap (mix / match) individual gears between 2.03, 2.43 and 2.46 ratio sets.
 
D-18's were never factory built using 2.43 gear sets  having the larger 1-1/4" intermediate shaft.
However one may swap the complete 2.43 gear set into a 2.46  case in order to utilize the larger 1-1/4" intermediate shaft.. Or vice versa.

2.43  gear sets will certainly fit into the big hole cases but it would be impossible to build it as a D20 without the extra output gear required for D20's.
That additional gear was never produced.

It is possible to build a 2.46 ratio D20 but only if you find the rare 2.46 (5th gear) required.
Those rare 2.46 ratio TC rear output gears were only used in early Bronco transfer cases.
The Dana Spicer part number is 18-8-58.

And finally it's also possible to place 2.03 ratio gear sets into the small hole transfer cases. 
Of course the extra 5th TC output gear is not used in the D18.

Other rarely seen transfer case combinations are certainly do-able.
I will detail some of these under the heading  "modifications from original" .

In the modification forum I will delve into various aftermarket upgrades and related concerns.
Like building of the "SUPER"  Dana  18.

And it's also possible to reconfigure the D20 into an amazing Unit.

See you there......


Edited by oldtime - 18 Sep. 2018 at 7:28pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rick G Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep. 2018 at 1:35am
Ken, am I to understand that both of these cases are D18?  Is one simply a small hole D18 and the other is a large hole D18?  

I presume these are the same two cases just flipped over.  So, does the presence of the large hole and two shift rail thimbles define a D20 case or simply a late model single stick D18?

What I'm really wanting to know is what is the difference between a late model, large hole D18 case and the D20 case.  I understand that the D20 has an extra gear in it and it was a centered output, but are there actually any differences between a large hole D18 and a D20 case?


Edited by Rick G - 03 Sep. 2018 at 1:57am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote chasendeer Quote  Post ReplyReply Direct Link To This Post Posted: 03 Sep. 2018 at 10:14am
Originally posted by Rick G Rick G wrote:

Ken, am I to understand that both of these cases are D18?  Is one simply a small hole D18 and the other is a large hole D18?  

I presume these are the same two cases just flipped over.  So, does the presence of the large hole and two shift rail thimbles define a D20 case or simply a late model single stick D18?

What I'm really wanting to know is what is the difference between a late model, large hole D18 case and the D20 case.  I understand that the D20 has an extra gear in it and it was a centered output, but are there actually any differences between a large hole D18 and a D20 case?

A large hole Dana 18 will only have one shift rail sticking out the back, a 20 has two. You can use both to build a 18 with.
Jay

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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep. 2018 at 11:33am
Quote Ken, am I to understand that both of these cases are D18?  Is one simply a small hole D18 and the other is a large hole D18? 

They both have potential to be D18.
Only the big hole case has potential to be a D20.

Quote  What I'm really wanting to know is what is the difference between a late model, large hole D18 case and the D20 case.

This detail depends on several factors such as Jeep vs IH but basically  upon the vintage of the assembled case.
There are many slight perhaps irrelevant differences between various big hole castings.
I only covered what I thought to be the significant concerns.

Location of the tapped lube fill hole and weather or not its tapped to accept clutch control pivot stud.
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep. 2018 at 11:34am
Quote  A large hole Dana 18 will only have one shift rail sticking out the back, a 20 has two. You can use both to build a 18 with.  Jay
 
NO ! Disregard that statement.

The main casting is not the transfer case.
Let's not confuse the main casting with the model of transfer case.
That's why it's best to refer to the main casting as either big hole or small hole. 
Not D18 nor D20.
The original application of a main casting is in most ways completely irrelevant to the model of transfer case one plans to build.
 
The small hole castings will only ever have 1 shift rail pocket with no exceptions !
A D20 can never be built from any small hole casting. 

The D20 must be assembled in big hole casting . 
All big hole castings will always have 2 shift rail pockets with no exceptions.

And so a Big Hole D18 will also always have 2 shift rail pockets even though one of the shift pockets is not being used for it's construction. No exceptions !

After my last post here on 30 Aug. 2018 at 11:43am I begin to detail D18 and D20 build concepts.
I do not consider that info to be historical reference so I moved the continutation of this  discussion back over to the modifications forum. 

See: https://www.thecj2apage.com/forums/transfer-case-upgrades-and-modifications_topic43110.html
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stev Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 11:38am
Oldtime,

Can you explain the pros and cons of having the cross shaft changed from needle bearings to tapered roller bearings.

Thanks,
Stev
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 11:44am
Yes,  ready to post some more  on building transfer cases  SOON...
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jbjeeps Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 3:40pm
Oldtime: I'm searching for a big hole transfer case that I can put Tera Low gears in and put behind a T90C. I am in touch with the owner of this case.  I think it's the right case. Can you confirm that for me?


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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 4:36pm
This particular TC is mated to a T14 transmission with the Jeep factory D-225 bellhousing adapter
So this is the famous 1967-1971 Jeep factory "Big Hole" D18  transfer case with single stick shift bearing cap .
An excellent unit for your needs.
Remember to ask about its previous application.
Standard for this unit will have 3.73 speedometer gears and optional had a 4.89 speedometer gear set.

This Big Hole transfer case obviously has the side fill plug and will also be tapped to accept the clutch control stud !
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jbjeeps Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 4:58pm
Originally posted by oldtime oldtime wrote:

This particular TC is mated to a T14 transmission with the Jeep factory D-225 bellhousing adapter
So this is the famous 1967-1971 Jeep factory "Big Hole" D18  transfer case with single stick shift bearing cap .
An excellent unit for your needs.
Remember to ask about its previous application.
Standard for this unit will have 3.73 speedometer gears and optional had a 4.89 speedometer gear set.

This Big Hole transfer case obviously has the side fill plug and will also be tapped to accept the clutch control stud !

Excellent! Thanks for your quick reply! 

Jack
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rick G Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep. 2018 at 10:57pm
Originally posted by oldtime oldtime wrote:

Quote Ken, am I to understand that both of these cases are D18?  Is one simply a small hole D18 and the other is a large hole D18? 

They both have potential to be D18.
Only the big hole case has potential to be a D20.

Quote  What I'm really wanting to know is what is the difference between a late model, large hole D18 case and the D20 case.

This detail depends on several factors such as Jeep vs IH but basically  upon the vintage of the assembled case.
There are many slight perhaps irrelevant differences between various big hole castings.
I only covered what I thought to be the significant concerns.

Location of the tapped lube fill hole and weather or not its tapped to accept clutch control pivot stud.

So all of these questions were spawned by your response to one of my posts in the T90C vs T90A thread that was started by Stev, where I commented that I bolted a twin stick front bearing cap to a D20 case.  I hope that I didn't imply that I built a D20, because I know I didn't build a D20. This was your response to my comment:

Originally posted by oldtime oldtime wrote:

RickG,  your running a Dana 18 transfer case... not a Dana 20 transfer case.
If the big index bore casting was removed from a Dana 20 that does not imploy that you built a Dana 20.

Dana 18's were factory available with either the Small hole (3-5/32" index bore) or Big hole (4" index bore) cases

The twin stick Dana 18 front bearing cap simply will not work with the D 20 transfer case.

So this had/has me very perplexed.  I built a D18 transfer case with Rockeater gears and a twin stick front bearing cap.  What I started with was not my original D18, but a single stick, dual thimble, large hole case, that based on the casting number, indicated that it was a D20 (at least the case).  It was built as a D18 with the offset output, however.  I believe it came out of a mid-late 60's CJ5 (?).  I understand that the internals are different between the D18 & D20 but my confusion was predicated on the fact that I believed the D18 large hole and the D20 case are essentially the same, however your response to my comment in the other thread confused me.  

I think this is what I'm understanding from the bulk of your notes here in this thread.  That is, the large hole D18 and the D20 (assuming both are jeeps) case are nearly identical and interchangable?  You can build either a D18 twin stick or a D20 single stick from the large hole, 2 thimble case, am I correct in understanding this?

BTW, thank you for sharing your vast jeep knowledge with me and others.  I have learned a great deal from you.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep. 2018 at 11:30am
Quote So all of these questions were spawned by your response to one of my posts in the T90C vs T90A thread that was started by Stev, where I commented that I bolted a twin stick front bearing cap to a D20 case.  I hope that I didn't imply that I built a D20, because I know I didn't build a D20.

Yeah Rick I do follow what you stated.
In fact I believed from the git go that you had a big hole D18 and it was potentially assembled (unknown) using some parts from a D20.
I merely brought that up to hopefully clarify some things for everyone who reads here.
Technically a complete transfer case is termed as a Transfer Case Assembly.
Refer to your Universal Parts List (UPL) or Universal Parts Catalog (UPC).
Only a select few of the individual components can be designated as D18 or D20 parts because so many of the parts are directly interchangeable. 
This specifically implies TC assembly components using the exact same part number.
And so the development of the "silent type transfer case" became an ingenious interchange of parts.

Quote  What I started with was not my original D18, but a single stick, dual thimble, large hole case, that based on the casting number, indicated that it was a D20 (at least the case).  It was built as a D18 with the offset output, however.  I believe it came out of a mid-late 60's CJ5 (?). 

Glad you mentioned casting numbers.
Casting numbers are DS part numbers used to identify specific castings. 
They are not a reliable source that can be used to identify a part. 
Castings are often (but not always) machined in different ways in order to produce different parts.
So two different parts may or may not have the same DS casting number.

Sometime around the late 1960's "transfer case assemblies" were being tagged with a part number specific to the assembly. 
In other words these id tags could be used to designate the specific components required to build the entire assembly.

These transfer case assembly tags have Jeep numbers from the early 1970'S:
They were attached to rear of  case via the intermediate shaft lock tab bolt

The TC ID tags if present can be used to identify the exact model of Jeep and approximate the vintage.
But modified units like a "Super Dana 18" for example will never have a viable ID tag.

 
Quote I believed the D18 large hole and the D20 case are essentially the same,

Yes they are the same but not in all instances.
For example: a late big hole casting removed from a D20 will have the fill plug on the rear and that was never true with the D18 big hole cases.
Perhaps I will check to compare late (1976 on) big hole casting numbers with some earlier big hole casting numbers.

Quote  That is, the large hole D18 and the D20 (assuming both are jeeps) case are nearly identical and interchangable?  

Absolutely true !

Now  to further our interchange knowledge .....that is also true concerning many but not all of the International Harvester  D18 and D20 parts.

IH Scout was a very strong competitor with Jeep from the early 60's into the early 80s.
One way in particular, IH Scout out distanced the  Land Rover and Land Cruiser competition.
IH was obviously American made and they were using the exact same Dana Spicer drive train components.
In a few instances IH was using certain DS drive train components that are IMHO blatantly superior to what Jeep installed on their vehicles.

I'll get into that more as required. 
Our discussion concerning transfer case progressions and modifications has certainly not been exhausted.

Unless we really know and understand all of the time proven old school technology how could we ever hope to rightly advance our knowledge into modifications and prototype development ?






Edited by oldtime - 08 Sep. 2018 at 5:01pm
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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