NP231 Transfer Case Problems

i have a '91 Xj and i am having a problem with it. For some reason i cant pull the lever into 4Lo like it just wont go down and if i do get it in 4Lo i have a hell of a time trying to get it back in 2 wheel or even 4H. Another problem is every once in awhile when i am in 4H it will pop out. anyone got ideas on why it is doing this

Auto or manual? If auto you really need to be in N gear and preferably rolling slowly for the shift to low range. Back to high, again in N gear but you can actually be rolling pretty fast w/out alot of gear clash. If manual, same but you could have problems trying to shift w/ trans in gear if the clutch is not releasing all the way. With either trans, the shift linkage for the t-case needs to be properly adjusted. If its popping out of gear ever, adjust. Put it in 4wd high, then loosen the bolt on the shift linkage under the Jeep. If its out of adjustment, it should move slightly when you loosen the bolt. Obviously this can be hindered by the linkage being dirty/corroded, etc but usually a little wiggling will do the trick. Then tighten the bolt and test. Good luck

Brian

whenever i tried to put it in 4H i would be in neutral and it would go in no problem.... but for some reason even in neutral going about 2 mph trying to shift it into 4Lo it would sounds like there is a lot of grinding and to me that grinding doesnt sound good... because in my friends xj which also has a NP231 it will go in smoothly but not for me. i have checked the oil and the oil is fine

Auto or manual, and is your friends auto or manual? There is typically more gear clash w/ the autos, so take this into account. Some gear clash is OK. The low range set is a constant mesh planetary gear set. The clash is not coming from the gear teeth themselves but rather the shift collar which either engages the input gear directly, or the planet carrier when in low range. From 2-4 hi it is shift on the fly. You can shift at pretty much any speed you like as long as everything is in working order.

Brian

mine is auto and so is his....but the major problem for me is that i cannot pull it into 4L without having to put muscle into it and yes i am in neutral going about 2 mph

Tried adjusting at all? Try disconnecting the linkage at the t-case shift lever and move it there to verify that the t-case itself shifts ok through all positions. If so, then look for binding in the linkage somewhere. The bushing where the inside lever pivots could be tight from lack of use in 4 lo. I have seen some where you couldn't even move the lever from 2wd because it had never been moved.

Brian

how do i go about removing the shift lever? yea when i started putting it in 4 wheel drive it was the 1st time in 12 years that it was ever put in 4 wheel drive

Just pull the linkage out of the shift lever for now. There is a plastic or rubber bushing where the round link rod connects to the flat metal lever on the t-case. Use a prybar or something similar to pop it out. The bushing may come with it. I can't remember which way the pattern goes, but if you start in 2wd, you should be able to move the lever from there to 4hi to n to 4lo and feel a detent in each position (may need to use some leverage here also). When the linkage is off, also try moving the lever inside. It should pretty much flop around easily from in there. If it doesn't your problem lies in the linkage. Im guessing you realize the shifter has to be nudged over to get from the 4hi position to n and 4lo.

Brian

yea i know that well prolly one of these days i will take a look at everythng you have told me since i work all xmas eve and i work on xmas thnx for all your help...and if the linkage is bad what can i do about fixing the linkage

If its the inside shifter pivot, I guess I would try just working it back and forth and try to get sny kind of penetrating lube into the bushing. Good luck.

Brian

explorer said:

If its the inside shifter pivot, I guess I would try just working it back and forth and try to get sny kind of penetrating lube into the bushing. Good luck.

Brian

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It's pretty common for it to get stiff if you don't use it a lot. Before going any further, I'd try doing the above, but don't give up too soon. Shift it back and forth at least 40 times. I have this problem with my Chevy truck - the bushing that goes through the floor gets stiff, and no amount of lubing seems to touch it unless you take it apart (fat chance!). So a couple of times a year, when it stiffens up, I just sit there and shift it until it softens up. It really can take 40 or 50 cycles to get it working right.

my 242 had the same prob., couldn't get it to fully disengage, caused damage to TC b4 I could get it to. Replaced TC and PB blaster-ed the heck out of linkage and made sure it moved freely b-4 tring new TC......works great now.....every chance I get I lubricate it and run it thru the gears to keep it free. Good luck w/ yours