NP231 Build, 2WD low, SYE, chain

Hey guys. I need a little direction on building up a 231... Something new for a change :laugh3:

Basically, I (eventually after lifting in the future) will need SYE. I figure while I'm at it, I can install a 2WD low kit, and upgrade the strength where possible, I'm thinking chain by popular consensus here. Really, I'm kinda after something to do haha.

I figure the best way for me to do this, and be able to take my time would be to pick up a 231 somewhere and go to town. This way I can still use my jeep while I'm building, as it is my primary vehicle. Then swap in the built 231, get new drive shaft, sell off my original 231. Here are my goals:

SYE, probably going to go with AA, they seem favored on here, and reasonably priced. 2WD low is just awesome, had it on my previous rig, and loved it. TeraFlex makes a kit, but I think the price is outrageous. Who else sells this? need opinions on that... Finally, beefy chain. Chain I have seen gets picked on. Whether its the weakest component, I could not determine... but seems that a lot of people suggest this. Again, not sure where to look as far as brand name... Other little things such as cleaning, inspection, replacing misc. parts (like the plastic pads) will take place here as well. I do not care to play with the planetary gears... I would love to be talked into it though! I think for the riding that I do, the low range gearing is just fine.

Any advice, thoughts, oppinions, criticism are more than welcome! I have never done this before, and I see a lot of you have. I have the time to do it right, and that's what I'm going to do, but I need your help.

Related future goals for my Jeep include Ford 8.8 rear, rear locker, 33s on about 5in of lift. Eventually, stroking to 4.6, 4.7. Just want to be sure that this build will be able to accommodate all that.

I am building for my 97 4dr Sport, with I6, AX-15, NP231, and stock axles.

Sorry for the long post, but just wanted to get everything out there. Thank you all in advance!!

Since it sounds like a mainly DD with no serious wheeling,I would just do the HD sye kit and maybe the 2low kit.The wide chain seems overkill for you(without the 6-gear planetary it doesnt make much since anyway).

Sounds like some pretty cool plans!

230 bucks is nowhere near as bad as I expected for the 2low kit.

Another way you could set this up is to swap in a vacuum disconnect front axle and use a vacuum switch of your own to select 4wd vs 2wd instead of having the transfer case choose. Then 2WD low would simply be 4WD low with the vac disconnect disengaged.

Another benefit would be a stronger passenger UCA mount, the only downside I can think of is that the vac disconnect housing might be weaker due to the extra junctions in the passenger axle tube, though I've seen people say it's stronger as well. To keep the larger u-joints on the front axle you'd also have to pull a passenger side shaft out of (I think) a 95 YJ.

Contrary to popular belief, if you are running a lunch box locker in the front, the vacuum disco really only drops you to three wheel drive. It will still turn crappy on slickrock and tight corners. I know, I tried that and it did help a bit but the turning problem still existed.

Good point... hadn't even thought about how it'd behave with a front locker.

You need the SYE and the heavy output shaft. Many folks make the 27 spline output shaft live forever, but just the wrong bounce on a big ledge (like in Moab) can take out that shaft. The 2low is also really nice, as it gives you better control and potentially better turning when you ned to go slow but don't need 4wd, and it saves unnecessary wear and tear on the drivetrain.

Personally, I wouldn't bother with the wide chain. No one breaks chains, they end up stretching and wearing out but that doesn't happen very often. They stretch prematurely from lots of running on hard surfaces in 4wd, but the 2low kit eliminates much of that. Basically, with a 2low kit you don't need a wider chain. I stretched a chain in a couple years of hard wheeling, when I replaced the chain I installed a 2low kit and never stretched the chain again in many years (like 10) of hard wheeling.

But, if you want to replace the chain while you have the t-case apart, just for good measure, and you can find a smoking deal on the wider sprockets, go for it.

I would do the 6 gear planetary mod over the wide chain, especially if you are going to install a stroker in the future. If you are going to have it apart anyway though, why not just do it all? That way you will have a reliable case for many years.

OK... so juggling some mods... probably not going to do the chain then...

The 2Lo kit is only like, 2 parts... made of pure gold maybe?? Just think that's high... oh well... I guess if I want it bad enough, I'll pay for it... sucks to be a sucker...

I found a good deal on a t-case, but its off a 4cyl jeep... 21 spline?? I dunno if that is capable with my 4.0L? what do you guys think?

Your is a 23 spline.It will depend on the donor rig.
See here for more info:
http://www.novak-adapt.com/knowledge/np_nvg_input_gears.htm

I plan on basicly doing everything you mentioned here to my 231 when I swap it in with an AX-15 to replace the pucker when it goes bad. The planetary gears, SYE, and wider chain. Someone suggested the Low range kit to me as well, but is that mod at all related to the wider chain/sprockets? What I mean is, can I do both? or Only one. Anyways back on topic...

To the best of my knowledge yours should be a 23 spline input, therefore the 21 spline t-case would NOT work.

Best of luck with your build.

Paint

You can do both.

Here's some pretty good information:

http://www.pirate4x4.com/forum/showthread.php?t=351184

http://www.opiebennett.com/images/Jeep/D4-ford9-swap/Day 15/np231.htm

You can do the 6 gear planetary using some parts from a dodge or Chevy 231 transfer case. The case itself won't fit in your jeep but the internal parts will swap.

http://www.naxja.org/forum/showthread.php?t=1007477&page=6

Start at post 82 for a how-to on the six planetary gear upgrade using junkyard parts.

Is the 2 low kit an easy install with the t-case in the jeep? IMO its easier to take the t-case apart for an SYE than it is to remove the t-case.

I realize this is pretty well a long shot, but is there any kind of upgrade or modification to make the 231 a twin stick shifter? Thanks again,

Paint

Paintballpsyco2369 said:

I realize this is pretty well a long shot, but is there any kind of upgrade or modification to make the 231 a twin stick shifter? Thanks again,

Paint

Click to expand...

nope, no way to twin stick a 231.
D300 swap isin your future if you want front digs.

I have been looking more and more into upgrades and such the last few days and came across something that mentioned the 241 planetary gears will only fit in a transfer case from a '96 or newer. I found a transmission and t-case combo locally and would like to get it, the XJ is a 96 but the date on the T-case is 11 of 95. Possibly a stupid observation on my part, but would that mean I CAN NOT use the planetary gears from a 241 in that t-case?

Paint

Ok, found out that that T-case is I guess a model 96 due to the late month of manufacturing. So I still wonder, with the 6 planetary gear modification, does the MODEL have to be a 96, or the manufacture date in 96?

Paint