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TeraFlex Low 18 3.15 gears in Dana Spicer Model 18

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bobevans View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Topic: TeraFlex Low 18 3.15 gears in Dana Spicer Model 18
    Posted: 16 Jan. 2019 at 3:04am
Started to put a D18 transfer case together to see if I can go slower. This all started last year when I took my '48 CJ2A 4-wheeling at the Spring Willys Reunion. A group of us had a blast slippin' and slidin' in the woods. I thought it would be great to have a little more control in a few spots, so started looking into lower gears.
In an ironic twist, I had swapped lower gears in my '79 CJ7 several years ago. To do that, I took the gears out of a D18 and added them to that rare, unicorn of gears - a Bronco Dana 20 sliding gear. Thie changed my gear ratio from 2.03 to a 2.46. It made a HUGE difference crawling. I kept the Dana 18 donor case so I would have something to trip over in the corner of the shop. The ironic part is that I finally took that old case to the very same Willys Reunion and sold it for way dirt cheap. Here it turns out that the case, from a '71 V6 CJ5, was the rare case I needed to swap the TeraFlex low gears into! At least I also scored the unique Dana 44 flanged, offset rear axle.
Well, I couldn't find a similar case, so I ended up getting a large hole donor case from a mid - 70s CJ5 Dana 20. And of course, I had to find a Dana 18 front and rear bearing retainer, shift forks etc, so I ended up buying another whole Dana 18 case. Thankfully, I will have something else to trip over in the corner of the garage again .

Edited by bobevans - 16 Jan. 2019 at 3:39am
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 3:19am
First problem with this case from a Dana 20 is the oil fill plug. The location interferes with rear bearing retainer/parking brake and you can't get to it to fill it! The solution is to tap a new fill hole and plug the old. The D20 fill pan had just the right low profile, recessed square hole 1/2" NPT plug. I ran the tap into the case a little further and ran the plug into the 1/2 NPT die a couple of times to get a deeper fit. Then we had to drill and tap a new fill hole. I couldn't bring myself to drill into the case with a nearly 3/4" drill bit, so I stepped the size down to a 3/8 NPT hole. I used the thick boss where my Spicer 18 case fills now. As Luck would have it, this case was already tapped for clutch pivot stud and a place-holder bolt was keeping the threads clean.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 3:27am
Next challenge occurred (if we don't count the hassle of removing and replacing the output shaft bushing) when reassembling the front bearing retainer. The TeraFlex instructions say to remove 1/2" of the shorter shift rail to avoid interference with the intermediate gear. Taking a whole 1/2" off seems like that when the shift rod is all the way forward, the rear part of the shift rod would pretty much come clear out of the main case. I guess we'll have to go real slow and keep trying it in and out. It will def. hit the intermediate gear now, and I guess I'm going to have load up all the needle bearings and actually place the intermediate gear for a final check.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 3:34am
The instructions don't mention an interference with the underdrive shift fork (the bigger fork) and the output shaft sliding gear. Especially when I had mechanic's wire on the fork nut, the gear hits the collar of the shift fork. I have 2 different forks and both of them hit the gear. I'm going to clearance the collar of the shift fork, unless some one has a better idea. I think I will also use the later allen head set screw in the fork.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 3:50am
Nice!.... How did you get the case so clean ?. Looks like fresh casting! ๐Ÿ‘

Lee
               LEE
44 GPW-The Perfected Willys
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โ€œIf you wait, you only get olderโ€
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Stev Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 1:26pm
Very impressive work.  Cant wait to see this Jeep on the trail.  
Stev
1946 CJ2A Trail Jeep (The Saint), 1948 CJ2A Lefty Restored
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AKoller Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jan. 2019 at 2:34pm
Thanks for the post. I am planning on a Terralow upgrade this year on my Jeep. I have a big mouth (4") Dana 18 out of a late 60's CJ5 I will use. I will also replace the 2nd gear and synchro's in my T90 at that time to try to solve the jumping out of 2nd problem I currently have. I hope to have this done before the FCT in September if I'm lucky enough to get drawn to go.
1950 CJ3A "Thumper"
1966 M151 A1
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jan. 2019 at 2:15am
Originally posted by Lee (MN) Lee (MN) wrote:

Nice!.... How did you get the case so clean ?. Looks like fresh casting! ๐Ÿ‘

Lee



The machine shop right next to my office has a "hot tank". The same washing cabinet he uses for engines. Case, bearing housings, shift rods etc. were $30.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jan. 2019 at 3:07am
Originally posted by bobevans bobevans wrote:

Originally posted by Lee (MN) Lee (MN) wrote:

Nice!.... How did you get the case so clean ?. Looks like fresh casting! ๐Ÿ‘

Lee



The machine shop right next to my office has a "hot tank". The same washing cabinet he uses for engines. Case, bearing housings, shift rods etc. were $30.


Thatโ€™s cheating! ๐Ÿ‘๐Ÿ‘๐Ÿฝ๐Ÿ‘

Lee
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โ€œIf you wait, you only get olderโ€
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ol' Unreliable Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jan. 2019 at 4:07am
I see the nearly-ubiquitous Harbor Freight special 27-LED portable worklight there.  Those are the best things HF has ever given away!  Thumbs Up
There's a reason it's called Ol' Unreliable
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepFever Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jan. 2019 at 4:47am
Originally posted by Lee (MN) Lee (MN) wrote:



Thatโ€™s cheating! ๐Ÿ‘๐Ÿ‘๐Ÿฝ๐Ÿ‘
 
 
  I was thinking same thing.  LOL     
 
Looking forward to the "rest of the story"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ndnchf Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jan. 2019 at 11:31am
Originally posted by Ol' Unreliable Ol' Unreliable wrote:

I see the nearly-ubiquitous Harbor Freight special 27-LED portable worklight there.  Those are the best things HF has ever given away!  Thumbs Up

The current light has a single bar LED rather than a bunch of individual LEDs.  Also their freebie little pocket flashlight has gone to single, very bright LED rather than a bunch of small ones.  It is brighter and more focused.  Constant product improvementWink
1948 CJ2A - It goes nowhere fast, but anywhere slow.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan. 2019 at 12:51am
Bob you and Steve got me all excited on this topic so I decided to put another one of my transfer cases together today.
This one is going to be a big hole D18 with a Tera low gear set plus tapered Intermediate shaft bearings.
Parts were all setting since last fall and ready to assemble.

Quote  The TeraFlex instructions say to remove 1/2" of the shorter shift rail to avoid interference with the intermediate gear.
I don't have any instructions but found that my large intermediate gear barely clears the short shift rod with the poppet ball engaged into its position.
When I get back at it tommorrow I think that I'll cut 1/8" of from the short shift  rod.
Yes the intermediate gear and the out put shaft must be in their proper positions to determine the working clearance.
My big sliding gear just cleared the large shift fork so I left the fork "as is" without additional grinding.

By the way Bob, those are great pics that you posted.
I can see what it takes to get a camera along with good lighting into that confined space.

I'll probably button mine up tomorrow...






Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike F Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan. 2019 at 1:21am
I think Iโ€™ve decided I need one of these. Along with a T90C and 4.11 gears in the axles

Edited by Mike F - 18 Jan. 2019 at 1:23am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan. 2019 at 2:03am
Originally posted by Lee (MN) Lee (MN) wrote:

Originally posted by bobevans bobevans wrote:

Originally posted by Lee (MN) Lee (MN) wrote:

Nice!.... How did you get the case so clean ?. Looks like fresh casting! ๐Ÿ‘

Lee



The machine shop right next to my office has a "hot tank". The same washing cabinet he uses for engines. Case, bearing housings, shift rods etc. were $30.


Thatโ€™s cheating! ๐Ÿ‘๐Ÿ‘๐Ÿฝ๐Ÿ‘

Lee

Wait, did I say hot tanked? I meant to say I scrubbed the case clean with a toothbrush. Yeah. An NOS, natural hog hair bristles toothbrush. And Murphy's Oil Soap. Yeah, that's what I meant to say.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan. 2019 at 2:06am
Originally posted by oldtime oldtime wrote:

Bob you and Steve got me all excited on this topic so I decided to put another one of my transfer cases together today.
This one is going to be a big hole D18 with a Tera low gear set plus tapered Intermediate shaft bearings.
Parts were all setting since last fall and ready to assemble.

[quote]ย <span style=": rgb248, 248, 252;">The TeraFlex instructions say to remove 1/2" of the shorter shift rail to avoid interference with the intermediate gear.
</span>
<span style=": rgb248, 248, 252;">I don't have any instructions but found that my large intermediate gear barely clears the short shift rod with the poppet ball engaged into its position.</span>
<span style=": rgb248, 248, 252;">When I get back at it tommorrow I think that I'll cut 1/8" of from the short shiftย  rod.</span>
<span style=": rgb248, 248, 252;">Yes the intermediate gear and the out put shaft must be in their proper positions to determine the working clearance.</span>
<span style=": rgb248, 248, 252;">My big sliding gear just cleared the large shift fork so I left the fork "as is" without additional grinding.</span>
<span style=": rgb248, 248, 252;">
</span>
<span style=": rgb248, 248, 252;">By the way Bob, those are great pics that you posted.</span>
<span style=": rgb248, 248, 252;">I can see what it takes to get a camera along with good lighting into that confined space.</span>
<span style=": rgb248, 248, 252;">
</span>
<span style=": rgb248, 248, 252;">I'll probably button mine up tomorrow...</span>
<span style=": rgb248, 248, 252;">
</span>
<span style=": rgb248, 248, 252;">
</span>
<span style=": rgb248, 248, 252;">
</span>




Great! I must have read and re-read your transfer case information about a dozen times so far.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lee MN Quote  Post ReplyReply Direct Link To This Post Posted: 18 Jan. 2019 at 3:58am
Originally posted by bobevans bobevans wrote:

Originally posted by Lee (MN) Lee (MN) wrote:

Originally posted by bobevans bobevans wrote:

Originally posted by Lee (MN) Lee (MN) wrote:

Nice!.... How did you get the case so clean ?. Looks like fresh casting! ๐Ÿ‘

Lee



The machine shop right next to my office has a "hot tank". The same washing cabinet he uses for engines. Case, bearing housings, shift rods etc. were $30.


Thatโ€™s cheating! ๐Ÿ‘๐Ÿ‘๐Ÿฝ๐Ÿ‘

Lee

Wait, did I say hot tanked? I meant to say I scrubbed the case clean with a toothbrush. Yeah. An NOS, natural hog hair bristles toothbrush. And Murphy's Oil Soap. Yeah, that's what I meant to say.


Thatโ€™s more like it! ๐Ÿ˜‚๐Ÿ˜‚๐Ÿ˜‚

Lee
               LEE
44 GPW-The Perfected Willys
49 2A
โ€œIf you wait, you only get olderโ€
67 M715
American Made Rolling History
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2019 at 5:51am
Ken, You're not missing much if you don't have the TeraFlex directions. There is this little intro and then the rest of the directions are 2 pages of reprints of a Haynes or Chilton manual.
'48 CJ2A

'56 DJ3A

'79 CJ7

And two of them actually run!
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