Humming/vibe on hard accel and cruising at ~70kph in O/D

[Function > Form]

Hey all, I've already been all over the liberty boards, but the number of mechanical experts is a little thin compared to here. Hope you can shed some light on these two slightly annoying issues before they get worse/something goes boom.

Issue 1:
NP242 while in 4x4 only, whether 4H or part time, it will hum/vibrate while cruising (light load) at about 70 kph (~1500 rpm or so in overdrive). If I turn O/D off, it goes away immediately.
It only does it in O/D, does not do this in any other...

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[2Greys]

Pull both drive shafts one at a time and see if vibe goes away. If it does, head to Ottawa Driveshaft and have them look it over.
That would be my guess for at least #1, for #2 is it speed based at all?
#2 skip moog the next time and get spicer. They aren't as good as they used to be.

I find u-joints aren't worth the hassle looking at (well if you are in decent proximity of a drive shaft place) for what it costs to get a new one replaced especially if it hasn't been changed in a long time if ever. I would pull the driveshaft drop it off in the morning on the way to work and pick up end of day.

 

[Function > Form]

Thanks [MENTION=272]2Greys[/MENTION] for some reason, I didn't think of pulling the shaft duh. Newb question - can I just put it in 4H with the rear shaft out? Would it work the same with the lib being IFS?

Yeah I know I K!N!O!W!! about spicers lol it's what everyone says. I just bought what was in stock because I needed them at the time. I did u-joints because I hadn't done them before - pretty easy tbh. Plus by the time I get down to ODS and back, I could almost have replace two for free...

#2 no it is not vehicle speed based. Seems to just be when I mash the go pedal, and the engine revs go over 3k - but only on WOT. IIRC, on part throttle - no vibe.

 

[junkpile]

You'll be able to feel that the joint is bad without needing to drive it. BUT if you had to you could as long as you tape a spray can cap or bag or whatever fits to that accordion looking dust shield boot hanging off the back of the t-case. Or you'll likely end up with a big mess and an empty t-case.


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[2Greys]

You'll be able to feel that the joint is bad without needing to drive it. BUT if you had to you could as long as you tape a spray can cap or bag or whatever fits to that accordion looking dust shield boot hanging off the back of the t-case. Or you'll likely end up with a big mess and an empty t-case.


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Pretty sure that isn't the case with the Liberty. I know you had to do that with the YJ but with the TJ and later you could get away with removing the rear shaft.

Not sure but could it also be pinion angle and getting it out of alignment due to axle wrap?

 

[Kunker]

Pretty sure that isn't the case with the Liberty. I know you had to do that with the YJ but with the TJ and later you could get away with removing the rear shaft.

Not sure but could it also be pinion angle and getting it out of alignment due to axle wrap?

I had the front torsion bar mounts do something similar under high throttle applications on my S-10, although it was more than a vibration - the bars/mounts were smacking the frame.

 

[Function > Form]

Pretty sure that isn't the case with the Liberty. I know you had to do that with the YJ but with the TJ and later you could get away with removing the rear shaft.

Not sure but could it also be pinion angle and getting it out of alignment due to axle wrap?

It has a slip yoke, I don't recall any fluid leaking out when I dropped it last time and it was off for a good while when I went to the parts place. Does the SY mean it would leak out while driving?

Maybe the diff pinion angle, but what would solve it?

I had the front torsion bar mounts do something similar under high throttle applications on my S-10, although it was more than a vibration - the bars/mounts were smacking the frame.

lol the sound is (fortunately) not that bad

 

[2Greys]

It has a slip yoke, I don't recall any fluid leaking out when I dropped it last time and it was off for a good while when I went to the parts place. Does the SY mean it would leak out while driving?

Maybe the diff pinion angle, but what would solve it?



lol the sound is (fortunately) not that bad

If it is the partial 4wd like I had with mine it is a 231 which should be fine with no leaks.

With the lack of a double cardon you want the pinion output parallel with the TC output (if not then you get vibes). If you did a Slip Yoke Eliminator you would then have the pinion point towards the TC output. Well that is what you would do with a TJ, I would assume the liberty would be similar but may want to look into if this is.

 

[Function > Form]

No you had manual and 231, I have auto and 242 (I double checked the tag)

I could go SYE, but jeez $480 US to address a WOT vibe is not making sense to me. Maybe if I had plans to swap axles and go 35s lol

I'll pull the front shaft and see what is fixed and what is still just annoying.

 

[junkpile]

Shoot sorry 242, yeah she won't leak there's no extension housing on that case. Looks like this right?

This style of 231 seals on the shaft if not plugged/capped it will leak,

I somehow had the two muddled together in my mind. I think for some apps they even had a 231 with the same style output as the 242 but I could be wrong.....again


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[Function > Form]

No worries dude - so many variations - it's like the 1st pic, splines extend out and are covered by the accordion/no metal cone.

 

[Function > Form]

It was a rear ujoint... Started squeaking after work Thursday so got the shaft out on Friday. More crumbled pencil leads in two of the trunion caps! Vibes gone.

One more thing off the list..........