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atlas II/ early aw4/ NP242 swap

J

jeepnuts311

NAXJA Forum User
Location
Atlanta, Georgia
hey all,
i have a 1990 4.0/aw/np242 combo and i have stretched two chains in my 242. when i was running stock tires, i used the full time a lot, but now that im running 33s and a rear locker i never use full time (my chain is stretched so i cant really). i was thinkin about going with a gear driven case like an atlas.

couple of questions regarding atlas t-case and my xj..

1. i have a non vac disconnect front axle, can i use an atlas with that? i dont want to do hubs or anything like that

2. does anybody have an atlas mated to an early style AW4 (21 spline)?

thanks
-tim
 
Last edited:
atlas is not chain driven......... It's gear you could just save some money and go for the 231 they are pretty stout and probally will be able to take your abuse.
 
I think your could easily get a 231 to hold up, but if you have the money for an Atlas, buy away! at the same time I would at least consider the new STaK cases, and consider swapping a 23 spline AW4 so you have a more common, and resellable, t-case.
 
BrettM said:
I think your could easily get a 231 to hold up, but if you have the money for an Atlas, buy away! at the same time I would at least consider the new STaK cases, and consider swapping a 23 spline AW4 so you have a more common, and resellable, t-case.
Click to expand...

so, i should get a new tranny so i can sell my t-case? no thanks. swapping input gears in t-cases is easy
if i cared what everybody else had, i would swap my 242 for a 231, but building a custom rig is exactly that..custom. any parts i procure, build, modify are for me and my xj, not anybody else. if i was worried about resale, i wouldnt use a sawzall on the fenders and have a rattle can camo paint job.

-tim
 
The atlas II is a killer unit and can ordered with 21 spline input, I know I just ordered one for a guy last week............

Also if you are stretching chains you have a lube problem.......Id bet the pump is shot or not correctly installed
 
thanks for the answers, my 242 has the short front input, when looking at the atlas ordering spec sheet, i saw where you could choose 21 spline, but it didnt distinguish between the long and short input gears.

also thanks for the input on the 242, my friend rebuilt it for me, and he replaced the oil pump, but i think he used gear oil rather than tranny fluid. learned my lesson with trusting buddies...even if they know how to fix things, always double check, it didnt take too long for the chain to go out after that.

-tim
 
no it would not.......its too viscous to run through the pump....the TC was starved... I had a pump fail on the highway from cali to AZ just after a weekend of wheelin in JV about 500 miles of highway driving after pump stopped working the chain was toast....
 
jeepnuts311 said:
thanks for the answers, my 242 has the short front input, when looking at the atlas ordering spec sheet, i saw where you could choose 21 spline, but it didnt distinguish between the long and short input gears.

also thanks for the input on the 242, my friend rebuilt it for me, and he replaced the oil pump, but i think he used gear oil rather than tranny fluid. learned my lesson with trusting buddies...even if they know how to fix things, always double check, it didnt take too long for the chain to go out after that.

-tim
Click to expand...

they use a short input, that will work with either the long or short then, on the 2001 I just put one pn it needed a spacer to allow for a longerrr input, the short input should bolt right up
 
do you know the specs on the spacer? what years need it and what years dont? i read on another naxja forum that someone needed a spacer on their '88, so i would assume that my '90 would need one, too.

if i did need the spacer, is it included with the Atlas, or would i need to drop cash on that, too. i know they include the shifters and stuff, i would imagine they would include the spacer since it is necessary.

-tim
 
The spacer on the 01 cost me an additional 105.00 and I did not need one on the 88 I put one on. from what I have determined the speed sensor in the tail section adapter of the new 97 and up is in a different farther back location that is why the spacer was needed
 
The atlas spacer is usually needed when the output shaft from the transmission sticks out more than .500". I'm in the process of installing a flat indexed atlas in my XJ right now. I didn't need the spacer because my 23 splined output shaft from a 1996 AX-15 was sticking out .487" from the mating surface. I have read on AA site that the spacer is 1" thick and was free from them if it is needed. My atlas didn't come with it, but when I ordered it from AA they said they could said one if I called and asked. I bought the Atlas a 1.5 years ago, so the free policy may have changed.

Rob
 
xjnation,
Since you have done a couple of installs, what did you do about the tranny mount plate. It looks like I will have to either put some washers between the tranny and the plate to allow for the plate to clear the atlas; or I may be able to trim the plate enough to clear the atlas without compromising the strength of it. Also, how much of the tc shifter hole did you have to trim? I ordered the universal 5" shifter because when I return to the states I will be installing my NV4500. Unfortunately I think the 5" shifter is too long for the AX15 that I have now. It puts the twin sticks about 1" behind my 5sp shifter.

Thanks
 
on 2 I used the cable shifters and it worked very well easy can put em where ever you wish. on the 01 I just finished I made a 1" thick square tube spacer assembled to look like an "H" it raised up the atlas by 1" and I mounted it in the stock rotation as the XJ. U used the twin rod shifters and had to cut out about 1" wider and 3" longer to make sure I ahd full shifter travel under all situations

picture.JPG


I then made a small sheetmetal cover that slipped over the shifters and under the console. works very well and looks OK LOL
 
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