help rebuilding an NP231

[lethaldose]

i'm tired of my d*mn tcase leaking so i'm thinking of just buying a rebuild kit from
JB Conversions for around 150 bucks ... my question is how in-depth is this besides just the mechanics , mainly will i need any special tools ? and can it be done in a weekend because i need to minimize my down time because of work ... thanks for the help guys 8)

 

[Bounty__Hunter]

It can be done in a couple of hours, you'll need a pair of large split-ring pliers. Also a 12pt. 10mm socket for one of the case bolts. Everything else is pretty straightforward, you'll be surprised at how simple it is. Post if you need any help, or email me bountyhunter AT sija.org .

 

[currupt4130]

You'll also need a big socket for the front output, and make sure the split ring pliars are the duck billed type. Other than that, its not hard by any stretch of the imagination, just make sure you get the pump lined up when you put it all back togeteher

 

[lethaldose]

beautiful guys next pay day is the 20th so thats the way i'm going .. i didnt think it was too bad but i just wanted to make sure before i dove on it apreciate it alot

 

[Snitty]

There cant be enough emphesis put on the split ring pliers. If you get crappy ones, you'll know it. Try to get the flat, duckbilled ones like corrupt said, but it can be done with the pin style. As Bounty said, you'll need the 12 pt 10mm. You'll also need a 15mm regular socket for the bolts that hold the halves together. Some large screwdrivers and prybars will help pull the halves apart. I think there is one more size socket for the tailcone, but I can't remember the size.

 

[Jeepr]

Haha! I should have posted up before I messed with mine! I screwed around for about an hour trying to get the snap rings off. Then I went to Sears and got a decent set of duck-bill pliers, it was all down hill after that!

 

[lethaldose]

well its time... i'm gonna go ahead and order the rebuild kit so i can tackle it next weekend , the leaks are just to bad for me to keep driving it so i've got to do something .... anybody have a good site that sales the kits ?? i was thinking of JB Conversions any other suggestions ??

 

[skeezer]

Go to a junkyard and pull a 231 T-case from a Cherokee. My buddy did and it came stock with 4.10 gearing for $ 150.00

The only other thing you'll need is RTV sealant for 5 bucks.

 

[lethaldose]

Go to a junkyard and pull a 231 T-case from a Cherokee. My buddy did and it came stock with 4.10 gearing for $ 150.00

The only other thing you'll need is RTV sealant for 5 bucks.

now somebody please correct me if i'm in the wrong here ... but i was very extremly unaware that Tcases have gearing as in "3.73-4.11" ect ??? that statement just seemed odd to me but maybe i've just been in the dark for awhile

 

[wts]

Its incorrect to say x-cases have differential gear ratios.
2.72: or 4.:1 are the common NP-231 ratios.

You been advised about everything you'll need.

- 12pt for the top center bolt.
- Duckbilled ring spliers.
- Aligning the oil pump pickup in the output housing.

Support the transmission/x-case with a floor jack or jack stand and remove the skid plate.

Drain it.

Disconnect the front drive shaft.

Put the case in 4HI to use the weight of the vehicle to hold the yoke in place as you wrench it off. An impact wrench is nice.

Remove rear DL. If you dont have a SYE this is where you'll be glad you drained it :lol:

You can completly remove the x-case OR leave it place and split the case halves with it still in the rig. Unless your replacing the front input or the front output bearing or installing a 4:1 - I prefer to leave it in the rig as its less work.

There are two pry points (slots) on either side of the case. You'll want to use a larger screwdriver to gently pry the case apart at these points first.

Do not use too much RTV to seal the case back up. Use a thin 1/8" thick bead and flatten it with your finger. If you use too much it will squish out and float loose, possibly, clogging the filter.

G'Luck!

 

[skeezer]

I just did this last week on my buddy's Yj. Don't forget the to disconnect sensors and linkage on the T-Case and also use some dilectric grease to keep water out of the sensor.

Quadratec & 4WD Parts sells the rebuild kits, good luck let us know how you make out.

 

[mud4feet]

Go with the 4:1 if you can.......that's the ratio they put in the Rubi and also in the 4Banger (mine, anyway). You'll love the crawling capabilites!!