QuickNDirty

3" rough country AAL lift with control arms

AX15 transmission, NP231J transfer case

84k miles.

TC angle: -5*
Rear diff pinion angle: +5*

Changed the transfer case fluid before doing the test drive, filled on an incline so it may be slightly above the fill line.

This transfer case has the tail housing and slip yoke lubrication is with ATF (Mercon V) from the transfer case.

I decided to change out the U-joints on the rear driveshaft because I had some vibrations around 70mph. When taking off the bolts on the rear yoke I noticed one was not right.

I pressed in the new U-joints and they rotate with a little but uniform resistance so I'm pretty sure they're OK. The fit between the tabs on the yoke and the caps on the joints is very tight still. When I put the bolts back in I stripped (if it wasn't already stripped) one of the bolts but it still held in there pretty tight so I decided to drive around the block to see what would happen.

I now have a crazy clunking noise that I kind of had with the old U-joints but not to this degree of severity, so i strapped a camera down there and recorded this video.

http://vid1151.photobucket.com/album...hunking_xj.mp4

Could a loose strap be responsible for this noise? I feel the thunking when accelerating and decelerating, but it is most pronounced when braking. (good example at the end of the video)

I bought some U-bolts to see if I could do that mod but there isn't enough clearance for the nut to fit on, so my next plan is to use some 1/4" grade 8 round head bolts with lock washers and nuts on the back side. Think that will work OK?

If it's not the strap, could it be the slip yoke? The slip yoke sticks out an additional inch or so after the lift and pressing up and down and left and right on the driveshaft allows the slip yoke to move axially about 2 hundredths of an inch or so. I may put a dial on that today. What is an acceptable value here?

Any other ideas what could cause this thunking?

QuickNDirty

Ok, I went ahead and installed the 1/4" bolts and nuts. Got them very snug and went for a test drive. Popping is still there.

I got up to some higher speeds this time. It's not 100% constant while accelerating, but when braking, the faster I'm moving the higher the frequency of the pops. It occurs even with the transmission is in neutral.

If my slip yoke has axial play, what do I need to replace to fix this issue?

QuickNDirty

=/ No one knows anything about this?

I took the DS back out just to double check and the joint at the TC didn't feel smooth like it did before I put it in after installing the new joints. Maybe I screwed up the install somehow?

I'm going to replace the joints again just in case, using moog joints this time since the last ones were precision joints from Oreillys.

Larry's XJ

Would your TV allow you to run just front or rear DS to eliminate them ?? Jack up axle and rotate wheel with and without DS, both front and rear. Ever service axles? New fluid, inspection?

QuickNDirty

My TC will puke atf without the rear yoke in. Trying to figure out a way to secure it. I installed the new joints and am 100% sure I did it right. I put the cam on the rear diff and the noise is coming forward of that. I guess maybe it could be the front DS. I'll try jacking it up since I got my jack stands back from my friend.


Interesting thing, though. I tried driving slowly in 4wd on my flooded neighborhood street and the popping when turning is incredible and moves the vehicle. No popping when turning in 2wd. Is this because 4wd would resist turning more thus increasing the load on the rear?


Eta: holy hell this rain is intense. Houston is crazy weather lately.

QuickNDirty

Well that was illuminating...

With the rear jacked up I was able to tell pretty quickly that the rear drums are seized on both wheels or something. The rear right tire was hard to rotate passed one spot.

The rear left was easy to rotate but had some friction point in one spot as well.

What's weird is when I cranked it up. In first and second, no noise. In third, however, the rear left would kinda try to move every now and then, but the right would continuously move, and every time the rear left tried to move the tcase would make a familiar racket.

I figured the rear left would be the one moving since the right one had a spot where it would lock up. Didn't hear any funky noises from the rear diff but maybe what I was hearing in the tcase traveled up the driveshaft.

Also pushing and pulling on the rear right yields a single pop noise like a spring is snapping or something. I'm going to wait on it for today and take all that stuff apart tomorrow to see how screwed it is back there.

Too early to tell yet, but the runout on the driveshaft appears to be pretty small. Definitely going to get the mic on there. At least I know now that I can install u-joints in under an hour =/

I hope the transfer case is OK.

QuickNDirty

Got the rotors off. Without the rotors the hubs spin freely and don't bind anywhere that i can tell. I can push and pull the hubs on both sides in and out a little over half a milimeter, and they have some axial slop as well.

The rotors themselves I think have wallered out bolt holes and they are able to shimmy around in there, possibly making that noise I was hearing.

With the e-brake "fully" disengaged, the rear left drum appears to still be engaged. The rear right seems OK I think, but I don't have much experience with drum brakes yet.

Both rotors have weird wear patterns. The rear right doesn't have any grooves to speak of, but does have rust on one side and a smoothish pattern on the other. Not even sure how that's possible.

The rear left rotor has a groove all the way around it, and the shoes have a raised portion where that groove is, so that's probably been going on a while.



Rear left shoe with raised edge:



E BRAKE OFF, rear left appears to be engaged still:



E BRAKE OFF, rear right appears to be disengaged:



Rear right rotor, half shiny, half rusty:

QuickNDirty

I figured out how to reproduce the popping. Pushing up on the driveshaft near the tail housing while it is spinning causes the popping. Waiting on the video to upload now.

Any ideas what that could be?

Pushing left and right doesn't seem to do much, and pulling down on it yields a mild popping, but push up on it and the whole truck shakes.

QuickNDirty

Bent drive shaft. Got one from jy, smooth sailing now.