Topic: What do you guys think? U-Joints?

[jfrabat]

While driving back from San josé to Panama, I notice that the Jeep has a ritmic vibration coming from the rear (at least it feels like it's coming from the rear).  It is not the engine, as you feel no power loss whatsoever, and the vibration is aparent only with the Jeep in gear and under acceleration or deceleration.  The vibration is felt mostly in the mid speed range (25 to 45 mph).  I am thinking a bad U-Joint somewhere in the rear DS (the front one is always spinning, so a bad U-Joint would be indifferent if the Jeep was in gear or not).  What do you guys think?  i hope it at least lasts the rest of the trip, as I have nowhere to get new joints here in David, Chiriquí (halfway point between the 2 citites).  I still got about 300 miles to drive tomorrow!  (fingers crossed!)

[sharpxmen]

While driving back from San josé to Panama, I notice that the Jeep has a ritmic vibration coming from the rear (at least it feels like it's coming from the rear).  It is not the engine, as you feel no power loss whatsoever, and the vibration is aparent only with the Jeep in gear and under acceleration or deceleration.  The vibration is felt mostly in the mid speed range (25 to 45 mph).  I am thinking a bad U-Joint somewhere in the rear DS (the front one is always spinning, so a bad U-Joint would be indifferent if the Jeep was in gear or not).  What do you guys think?  i hope it at least lasts the rest of the trip, as I have nowhere to get new joints here in David, Chiriquí (halfway point between the 2 citites).  I still got about 300 miles to drive tomorrow!  (fingers crossed!)

if it's not the d/s then i'm thinking the R&P

you could lift the rear on jackstands and see if you can determine what's vibrating

[jfrabat]

if it's not the d/s then i'm thinking the R&P

I opened the rear one today (just an hour ago) and it looked fine...  So it HAS to be the DS.

[Jeffy]

Probably the U-joints if it's happening only when accelerating or decelerating.  At least the joints are cheap and it's a relatively easy job.  I recommend Spicer U-joints if you can find them.

[jfrabat]

Well, I think it IS the rear differential... 

First thing first; I noticed the diff was spitting oil through the front (the bearing where the DS attaches to the diff).  I then opened the diff again, and I noticed a couple of things; first, the pinion looks like it was taken to an angle grinder at some point in its life.  I do not know if this was when it was installed, or after I had some issues with with the diff (right after I installed the lockers and new gears and axles), but there are also some scratch marks on the ARB locker.

Here are some pictures I took last night of the inside of the diff; they were taken with my cell, at night, and at close distances to get what I wanted to show, so sorry about the crappy resolution and out of focus images!





Now, i am not sure this is the cause (the ring did look fine), or if it really is the U-joints. 

The Jeep DID make it home, but about 50 miles from home, the vibrations got REALLY bad, so we dropped the speed to 35 mph just in case it died before we made it.  Aside from the vibrations, I also got a rattle that is only audible when in gear (I can rev the engine all day long with no noise, but when I put it in gear, it starts on and off, so it's not the exhaust), and the AC compressors clutch is acting up (sometimes it shuts off, and it needs a little love tap from the big screw driver to get it to come back to life!).

[jfrabat]

More information (or images)... 

First, notice how the oil is seen from the front of the DS to all over the gas tank's skid plate...





And a short vid showing the DS play:

<a href="http://www.youtube.com/v/8XdXEX7fxDI?hl=en&amp;fs=1" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/v/8XdXEX7fxDI?hl=en&amp;fs=1</a>

<a href="http://www.youtube.com/v/eKxRr5_xbTE?hl=en&amp;fs=1" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/v/eKxRr5_xbTE?hl=en&amp;fs=1</a>

I am starting to lean towards U joints again...  What do you guys think?

[Torch_Ind]

if your pinion missing chunks of the end of it?? and your right it looks like it's hitting the arb carrier

you may have problems with both the pinion bearings and u-joints

[aw12345]

Nope no U joints. the nut on the pinion yoke came loose or the crush sleeve on the pinion collapsed some more. Either way the pinion moves in and out of the ring gear and there by rubs on the locker. Tighten the pinion nut and see if the play and the problem goes away and if it maintains about 25inch/lobs rotational torque with the wheels of the ground. If all else fails inspect the pinion bearings, replace the crush sleeve and call it good as long as there are no chunks of your ring gear and pinion missing they should both still be ok.
While you are taking it apart check both rear driveshaft U joints by moving them and feeling for roughness, stiffness or signs of rust coming out of the cups

[jfrabat]

Thanks, Art...  I was thinking along those lines.  I'll have to take the Jeep to a mechanic (or rather, my dad will do so), as I leave for Costa Rica tonight, but I was already set on him checking the rear diff, as that seems to be the cause of all my problems (well, the more important ones anyway!).

[sharpxmen]

Well, I think it IS the rear differential... 

First thing first; I noticed the diff was spitting oil through the front (the bearing where the DS attaches to the diff).  I then opened the diff again, and I noticed a couple of things; first, the pinion looks like it was taken to an angle grinder at some point in its life.  I do not know if this was when it was installed, or after I had some issues with with the diff (right after I installed the lockers and new gears and axles), but there are also some scratch marks on the ARB locker.

Here are some pictures I took last night of the inside of the diff; they were taken with my cell, at night, and at close distances to get what I wanted to show, so sorry about the crappy resolution and out of focus images!

looks to me like either your yoke nut was loose and the pinion is hitting the carrier (arb) if i make that picture correctl or could be that the outside pinion bearing is busted (for that much "play" to be in it).

[aw12345]

Hate to tell you this, but in the end you are going to end up running bigger tires and stronger axles so you can just wheel with impudence, get home park it, wash it and head out again the next day of need be. I am loving the big Jeep, for as much abuse as the beast has seen in the last 2 months it's hardly and worse for wear. Was well worth all the work and money. Seeing that you like to wheel and there are Nissan patrol axles available over there that come from the factory with lockers, are quite strong in stock form and have pretty good gearing choices you might want to scour your part of the world for a set of those so you can run something a bit bigger to get everything up and out of the mud

[aw12345]

looks to me like either your yoke nut was loose and the pinion is hitting the carrier (arb) if i make that picture correctl or could be that the outside pinion bearing is busted (for that much "play" to be in it).

The nut backing of is not uncommon and will cause that kind of wear on the ARB

[sharpxmen]

The nut backing of is not uncommon and will cause that kind of wear on the ARB

if it's new it shouldn't, reused one it might. that is if it's set to the correct preload with a new crush sleeve.

[aw12345]

The place that did the gears had it apart at least once afterwards and I doubt they used a new nut or used some red loctite on the old one. If preload was correct then the bearing should not have failed, I tend to go for the simplest answer and reason first which is the nut backed off. Old yokes tend to work on the splines a bit also is a good reason for it to work the nut loose

[jfrabat]

Well, I just hope the increase in vibration is not due to the ring and/or pinion loosing a tooth (or teeth!).  Today the tow truck will take the Jeep to the ARB distributor in Panama, and they will check to see what's going on...  Hopefully, no real damage will be found, but we will see today or tomorrow.