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Discussion Starter #1
Here is the current setup:

86 XJ with the 3.4l that replaced the 2.8l (I don't recommend doing that swap, btw)
AX5 transmission
NP231 from an 87 XJ, SYE installed
Axles I won't mention, but the front one busted a U-joint bouncing up some rock ledges.

What I am getting (for free):

NP203 from GM 3/4 ton

Dana 44 front
Corporate 14 bolt rear 4.10 r/p

My intention:

Mate the 203 to the 231 with a either a short single ujoint or double cardan driveshaft or possibly just remove the SYE flange and put a short shaft straight between the two xfers. With the swap of the axles, I will go from a drivers side drop to a passenger drop, so I believe the driveshafts will clear things with no problem.

I did some calculations and below is what I came up with for the different ratios. The configuration (if it was not clear) is AX5 -->NP231-->NP203. On the chart you will see it has configurations next to the ratios. H, H, 5 would be read as NP231 in High, NP203 in High, AX5 in 5th gear. L,H,3 would be NP231 in Low, NP203 in High, AX5 in 3rd. These ratios are just from engine output to 203 output.



The ones in green are the ones I thought made the most sense for use in shifting patterns. The one in yellow was one I didn't know how it would work as it was such a big jump between it (1st gear) and 2nd.

Ok, so my questions are:

1) Which way would be the best way to connect the 2 xfer cases? I could build some bracketry that would hold the cases together as one unit. But wouldn't there still be enough flex to cause binding on the shaft since they still might flex enough to act divorced?

2) Am I looking at this correctly as far as ratios are concerned? Anything else that I should be considering? I realize that it gets me only down to a 87.66:1 ratio with the 4.10's if I did the math right. But that is still better than the 39.87:1 that I have right now.

I looked over the web for someone else who has done this and didn't find one. That could be because a) bad idea to begin with or b) just normally not practical except with longer wheelbased vehicles.

I am operating on a shoestring budget. I have parts for fabricating brackets, and I can get the driveshafts done for no cost. I am going to shave down the 14 bolt and figure out how I am going to lock up the axles.

Other than that, give me some ideas and suggestions.
 

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I don't REALLY recommend doing this with an NP203. BUT, the concept is valid, and you could get moving until you found a small input/27 spline NP205 to replace the 203.....

The output shaft in your stock NP231 is the EXACT SAME 27 spline as the input of that NP203.

No flanges, No nothing. The input gear from the NP203 will slide right on. But seriously, a small input 205 is a better plan. (or go with the program described above....)

peace
Dave
 

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203 is also a very heavy and long tcase and huge...ive got one sitting in my hed and it prob weighs over 100lbs...
 

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I would not put a doubler in front of a 231, the 231 is just not strong enough. Buddy has a Klune on his 93 2.5L wrangler (4.88's and 35's) and broke the spline shaft between the klune and the t-case. He replaced the Klune to 31 spline with a 231 from a 4.0L YJ with the larger spline count. Few trips later he broke the shaft inside the 231.

zman
 

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Discussion Starter #8
The_freeak and gumbojeepyj -

I certainly would love to get one of those, but it sounds like they are 400+ dollars. And then I would have to find the 300. That is too pricey for me. Sounds like it is well worth it, but not practical for me.

famp - I read other threads on here where you can call the guy - just search.

mobs- yeah, the 203 I think actually weighs in about 165. It was just what I had immediately available. But I have decided that the NP205 is better.

zman-az - the 203/205 is after the 231, not before. Unless I am missing what you are saying, the 231 shouldn't be stressed beyond what I have done to it before on the trail.

rustywagoneersdotcom - thank you for the info. I have some people who owe me some things and I may just be able to get the 205 and axle for what I have already done in labor. Otherwise I will do a conversion on the full time axle I have.

I am pretty excited to see if I can get this to work the way I envision. Thank you all for your responses!
 
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