Stuck Transfer Case, NP242

[Wire Fox]

I was putting the linkages together for my NP242 and made the discovery that I apparently can only shift from H to HL and back. If it try to shift it farther into N (and L), it just won't go. I can feel a vague attempt at it moving, but it feels almost like metal flexing at the shift tab and it just won't budge anywhere. As I've learned more, I've come to realize that this is what the "Transfer Case Inop. - NMC" note was all about, and I wrongly (and quite naively) assumed that this was the replacement transfer case, when it really was the broken original.

I've read into the A1 troubleshooting guide and the only thing in the for the transfer case states that if the studs are installed too far in, it can prevent shifting into low gear. In trying to avoid dropping out the transfer case-or at least to make the most of it when I do-does anyone have any other ideas of what may be the problem? When I do take this down, I want to have several directions I can try to go to tackle this issue. As it is right now, the input shaft can be rotated by hand and it will cause both output shafts to rotate as expected. That's at least a vaguely good sign to me that the transfer case is operating in-gear, but just can't seem to change gears appropriately.

 

[daniel.7575]

If it has been replaced it could be possible that the linkages have been installed incorrectly, maybe try disconnecting linkage from lever and operating manually to be sure it's a transfer box problem not a shifting issue..

 

[Wire Fox]

If it has been replaced it could be possible that the linkages have been installed incorrectly, maybe try disconnecting linkage from lever and operating manually to be sure it's a transfer box problem not a shifting issue..

I just put on the shift linkages myself and was manually playing around with it from the linkage rod. The shifting lever on the transfer case itself was also just installed. That lever, when travelling away from the driver, will bottom out almost against the transfer case. I can manually pull the linkage away one gear/click and then go no farther; however, it feels somewhat springy like it wants to go farther but is jammed. In the other direction, it doesn't feel that way...just feels like it firmly isn't going to move anywhere-which would make sense if it's at the end of the gear range in that direction.

 

[Retiredwarhorses]

I had a similar issue on a Tcase on a full motor package, it suddenly dawned on me that the there was fluid dripping from the detent bolt on the bottom of the Tcase, when I went to turn it, it was loose..meaning? The fluid was drained at the demil yard from this detent bolt hole...when I took the bolt out, I found the detent missing and just the spring stuck inside the hole, all bound up and not wanting to come out...I finally pulled it out and and replaced the spring and detent...all issues fixed.

 

[Wire Fox]

I had a similar issue on a Tcase on a full motor package, it suddenly dawned on me that the there was fluid dripping from the detent bolt on the bottom of the Tcase, when I went to turn it, it was loose..meaning? The fluid was drained at the demil yard from this detent bolt hole...when I took the bolt out, I found the detent missing and just the spring stuck inside the hole, all bound up and not wanting to come out...I finally pulled it out and and replaced the spring and detent...all issues fixed.

I will definitely look into that. Anything I can test without actually dropping the T-case is a prime diagnostic check.

EDIT: Well, hello. I have the wrong connecting link installed, now that I'm looking at part diagram. That proper connecting link would be installed in a different direction than the NP 218 (my transfercase didn't have a connecting link installed, so I robbed it off the 218 I have, assuming they were the same). Seeing how it's shaped, I think that proper linkage (a straight piece of steel vs the cam/lobe shape for the 21 is in a bag of loose parts that I carefully rounded up when I first picked up the HMMWV. I'll correct this issue before further diagnostic so that I 100% have the correct baseline condition. If I'm lucky, the link may have been contacting the case where I couldn't see it, stopping the shfiting action. If that still fails, I'll follow through with the suggestion above to keep up the troubleshooting process.

...start with the simplest, work toward the hardest.

 

[Wire Fox]

If it has been replaced it could be possible that the linkages have been installed incorrectly, maybe try disconnecting linkage from lever and operating manually to be sure it's a transfer box problem not a shifting issue..

You win an imaginary cookie. Ultimately, I had the connecting link that bolts to the transfer case facing the wrong direction. When it's around backward like that, it perfectly hits the transfer case to give zero movement in a spot you can't see, but still clicking into gear nicely. I flipped it around and could clunk it through all four positions with the behavior changing each time as I rotated it by hand (could feel the difference in resistance...) It's still just a static test, but it seems to be working. I still now have the paranoia that this transfercase might be inop due to letter that was with my HMMWV, but I do think that this one might actually be different than the original...it's absurdly clean whereas every scrap part related to it left onboard was absurdly greasy and filthy, plus this thing was in a sealed plastic bag in the back...

 

[daniel.7575]

That's an excellent result! Your description certainly suggests the box has been swapped out.. Fingers crossed.
Thanks for the Cookie..

 

[tage]

whack it with a mallet.

actually don't do that. Some are like that. If you ever messed with the hemtt. The transfer case selector can be temperamental.