part-time 4wd noise and problems (dis)engaging

Hi all,

The 4wd (np242) in our 92 XJ has been a little problematic ever since we had the XJ (bought it 18 months ago with 145k on it). I have adjusted the shifting lever and changed the fluid, but it's still not great.

Part-time is easy to engage. However it is fairly noisy. Noise coming from the front, whining/grinding kind of noise. Might be normal, I don't know? If not normal, what to check? Then disengaging part-time is often problematic, requiring 5-10 times going back and forth (D-R) untill it will shift back to 2wd. Could this be related to the noise?

Getting into full-time is often a pain. The shift often gets stuck in part-time, and then it is again hard to get out of part-time (see above). Same when we go from full-time back to 2wd. Sometimes it gets stuck in part-time, with the same problems as mentioned. The full-time 4wd works great though. Once engaged it works perfect, and no noise as in the part-time mode. (so the noise is perhaps related to the locking of the diffs?)

Like I said I have adjusted the shifting lever and I think it's about as good as it can be. Anything obvious I should check? Does the shifting depend on vacuum? If so, could vacuum leaking cause this erratic shifting? Where to look?

Hope I provided enough info (if not let me know). I know little to nothing of the working and control of the 4wd and would appreciate any thoughts and ideas!

Tim

the 242 does not use vacumn.

check to see if you have the same tire pressure in all your tires and that there the same size and make.

are you shifting on the fly or when stopped?

have you moved it through all the gears manually without the linkage attached?

89xj said:

the 242 does not use vacumn.

check to see if you have the same tire pressure in all your tires and that there the same size and make.

are you shifting on the fly or when stopped?

have you moved it through all the gears manually without the linkage attached?

Click to expand...

Tires have the same pressure, they are same size. Rear is different brand than front, other than that they are pretty much identical (same wear).

I shift on the fly. For part-time I sometimes shift when stopped but for full-time I found that usually it works best by driving under throttle, shift, release throttle, and put throttle back on.

When adjusting the linkage I have manually pushed through the part-time and full-time, but I haven't checked if it would or would not engage when driving. Will experiment with that this weekend. I think the linkage is set-up ok (in the sense that the shift can physically be made), but it's interesting to see if I can shift it better without the linkage attached (if it makes any difference).

if you can move the gears smoothly by turning the shift rod manually, than it could have to do with the different make of tires. not all make/brand of tire is the same size even if there both say 225's. unless that only applys to 31's, 32's....

just trying to rule a few simple things out before you need to open up the case. im not that familiar with the inner workings of the case.

89xj said:

if you can move the gears smoothly by turning the shift rod manually, than it could have to do with the different make of tires. not all make/brand of tire is the same size even if there both say 225's. unless that only applys to 31's, 32's....

just trying to rule a few simple things out before you need to open up the case. im not that familiar with the inner workings of the case.

Click to expand...

Although I believe that there is no physical difficulty making the shift on the case, I will give this a detailed check in the weekend. Will also re-check (to the best of my tool's ability) tire presure to make sure that's ok and does not negatively affect the shifting. Don't have any spare tires to put on there to check if it (brand) makes any difference. Can I test shifting on jack-stands to by-pass the 'tire-effect'?

I guess the hard shifting is thus purely t-case related? No other mechanical parts that could cause that to not work properly? Just to narrow it down a little.

Thanks for thinking along!