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NP 208J to AX-15

M

MJlogan

NAXJA Forum User
Location
Upland, CA
I've been researching this swap for a little while as my 231 has been making some bad sounds lately. It seems to me like I need to make a 3/4" or so spacer and thats it. From what i gather, the Jeep 208 bolts to a tranny with a 23 spline shaft that is flush with the mounting surface. My AX-15 has a 23 spline shaft that sticks out 3/4" from the mating surface. Is this really all it takes to put a 208 on a ax-15 (besides linkage mods)?

from what i've read, everyone "thinks" you only need the spacer, but im curious if anyone has ever actually done it. Seems like a good setup- stronger than the 231, fixed yokes, strong outputs. only drawback is higher low range.
 
The NP208J is the rubicon t-case right?
 
The 208 is a case out of a fullsize jeep.I had thought about trying this conversion last year but finding a 21 pline is kinda hard so i gave up but they are tough cases.
 
oh, well im way off then.:banghead: what is the rubicon cases number then?
 
Gecko said:
oh, well im way off then.:banghead: what is the rubicon cases number then?
Click to expand...

The Rubicon has a 241OR transfer case.

What's a 208? I thought the full-size Waggies had a 228?
 
Yup, they had 208's- Not totally sure which models or if theres a way to tell which ones had 208s or 228s, but im sure they came with them. I think theyre more common in the J trucks and fs cherokees.

the 208 is what replaced the np203 and np205's in the 80s in most fullsize trucks.
 
don't know if that NP208 will mate to a AX-15 but I also just separated what I intially thought was a NP208 transfer case from a 86 XJ with the NP 207 transmission and discovered to my amazement after I split the case apart that the transfer case was really a NP228 from probably a larger older Wagoneer.Are you sure it's the NP208 ?-
 
Was the 208 used behind the manual transmissions in the full-size Jeeps? I'm fairly certain the Grand Wagoneers with auto got the 228.

The 228 and 229 were also used as the Selec-Trac option in the '84 thru '86 XJ. The 207 was the Command-Trac transfer case, not a tranny. The auto tranny back then was a Chrysler 904.
 
Theres a thread on Pirate that i was reading which led me here to see if you guys had any ideas. I some info form the AA website, thats where i found the input depth specs. I know they came behind the 727 autos, and am pretty sure they came behind the T176(?? i think..) or whatever manual they put in those things.

From www.jeeptech.com-

The NP208 has a aluminum case and an appearance similar to many other chain driven New Process transfer cases. It should have a tag on the back saying New Process Gear, Model 208. It is chain driven transfer case with a 23 spline input and standard round bolt pattern. The output for the front driveshaft is on the drivers side. Low range is around 2.62 and high is 1.00.

Usage
Full size Cherokees used the NP208 from '80-'83 and the J-trucks used it from '80-'86 or '87. The NP208 was the "Command-Trac" option for full size Jeeps during this time period.
 
btt.......Im gonna do it as soon as i can find a np208J in a junkyard. I'll let you guys know how it works out and what adaptation is actually needed. Then i can get my 231 out and try to rig up a dual tcase system......;)
 
correct me if I'm wrong but......

Isn't that a passanger drop case?
 
Oh yea Grand Waggys are......

but some of the other Jeeps that were mentioned I thought were not. That is why I asked that.
 
Blast from the past! I was net searching for some other NP208 info (as in how many Years Ford used the NP208F which is '80 to '88, 31 spline and the one I hope to sell is 31 spline) and I tripped over this post. I can attest that you can bolt the NP208J (or NP208D for RH drop) to post '90 AW4 transmissions (23 spline) but you need the thick (7/8") D300 clocking ring to do it.
 
I was under the assumption the NP208s came behind the Turbo 400 when it was used with the 5.9L AMC. I say this b/c this is what I was planning on doing.
 
Nope. Chev used NP208 with TH400 (and some others) I have the adapter sleeve and a 32 spline output shaft from a TH400 I was going to put in my '73 J4000's TH400. Jeep stopped using the TH400 in 1979. They used Borg Warner Quadratrac '73 to '79 and Dana 20 (with a weak factory adapter) with it in FSJs.
The Jeep 727 and 999 auto were used with NP208 '80 to '88 as an option.
 
Wow, i'm running a pass drop dana 300 now. Never got around to trying the 208.

If anyone is still into trying it, you'd probably have the best luck finding a dodge 208 if you want pass. drop. 23 spline and should bolt up to a later aw4 or ax-15 with a spacer.

To keep driver drop- good luck finding a jeep one. I know they exist, but havent come across one in the junkyard. Would be nice to find since they run a fixed yoke on both ends.
 
I happen to have a used Jeep NP208J for sale for $150 (in Seattle) and I see them here quite a lot. :D I took it off to put a Dodge NP208D on for my J4000 (which I'll get around to installing one of these days)
 
Just resurrecting this a bit. You can bolt a NP208J directly to an AX-15 with a 7/8" thick Dana 300 clocking ring or similar thickness spacer. I have a pic of it posted on the board someplace, but here it is again:
ax15np208j.jpg
 
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