Jeep YJ 4.0 NP231 Transfer case rebuild help!!!

ltrpilot9

ltrpilot9

Well-Known Member
Joined
Oct 15, 2012
Its a 94 YJ with a 4.0 and NP 231 transfer case, SYE kit installed.
I was driving normally, took my foot off the gas and the transfer case made a loud buzzing sound for a second then lost all power to the ground in every possible gear combination.

I removed the transfer case from the Jeep and now I’m at a decision point. I am considering paying someone to rebuild it, or maybe buying the kit and trying it myself. I am fairly mechanically inclined but I have never taken apart a transfer case before. Is this something that is smart to try?

If you recommend having someone else rebuild it can you point me to someone who can help?
 
It is very simple to do, you just need good snap ring pliers. There’s really not much to it. I’m betting a shift pad has fallen off and you are stuck between gears.

I have a lot of 231 parts, and have been in several. Not sure where you are at but if you’re not far I’d be glad to help. The snap rings are the worst part, I’ve successfully taken many apart without them but it’s time consuming.
 
Bet you the high low shift fork died. If that's the case, it was probably from lack of lube, so expect a few trashed bearings. I've got 231 pieces parts and a whole case. I'll try to remember to look you up a diagram, they're simple. Snap ring pliers can be found at advance for sure, and likely the other parts houses. The ones you want are "duck bill" tip and spread open when you grab the handle.
 
Or you could buy a good used case for $150 put that SYE on it and rebuild that one later.....
 
Sometimes choices get made for you. I ended up getting called out of town for work, so I dropped it off to get rebuilt. I think it was a good choice considering it was a catastrophic failure and i have no idea what right looks like. I will probably do a rebuild on my sons Jeep in the very near future.
 
Back
Top