Np231 advice

[John0061xj]

Ok sorry if I put the in the wrong section new to nc 4x4. Ok so I just got a 1999 xj with 4.0 amd AW4 with a broken np231j with a SYE already installed. T case housing is broke around output yoke that drives the front axle. I have another older np231 in the shop. My question is can I swap front half of the good tcase to the bad tcase? Or would it be better to swap the SYE to the older tcase and reinstall? What would be the better route and what would I need to make it work? I don't know year of older tcase but I do know it had a 4.0 and aw4. Thanks in advance for all help

 

[ol'Jeeps]

The SYE will fit any 231.

Just swap out the sye to the other 231, put a new chain in and keep diggin!

BUT...watch for...early 231s have needle bearings inside the sprocket. remove them and dont use em. Also, a lot of early 231 require the shift fork rail to be shortened. must be done but no big deal. SYE Instructions are all over the internets!

 

[a_kelley]

Only other thing would be if the new career came off a 90 or earlier model as it will have 21 spline input whereas you have a 23 spline

 

[ol'Jeeps]

Yep...missed that!

 

[thexjfiles]

If you put an old front half, on a newer case, the planetary from the newer case will fit, but they changed the cut of the teeth....and it will whine like hell and eventually destroy itself.

 

[ol'Jeeps]

yea. I have swapped parts around in a few NP231s. A lot to match up to get it right!