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Malfunction 06-21-2013 03:21 PM

Rear axle is moving @ banging
Dana 44 Rear axle, skyjacker lower control arms and Rubicon Express upper arms. The axle (pinion) is pivoting up and down when power is applied and it is making some terrible noises. The PO installed a spartan locker in the rear and going around corners is insane, the whole rear end starts banging and clanking around along with the jeep bucking wildly (feels like slamming on the brakes and releasing them in rapid secession) and that is with the clutch in. I can fell the whole drive train shifting around when the axle rotates, I just replaced the transmission mount, the old one was totally shot. Now that the new trans mount is in the movement in the rear end feels worse, I think its because the old worn out transmission mount was absorbing some of the force of the movement.

What causes this kind of axle movement? Im assuming its the upper control arm bushings because the lowers are heimjoints and I replaced them about 6k miles ago. Its really hard to wheel with it like this, I will have the clutch out and the gas steady and every few feet it the axle binds up and the jeep stops moving, then it unloads and we start moving again. and help would be greatly appreciated as this is the only problem I have left to remedy!

Malfunction 06-21-2013 03:25 PM

I did not put this lift on by the way, all done by the PO. Strangely enough after posting the mall crawler wheels on craigslist, the original owner contacted me. Im owner number five so I have four owners worth of problems and mistakes to fix!

freeskier 06-21-2013 03:34 PM

10 Attachment(s)
First thing I would check is to make sure the control arms bolts are tight.

BLK00TJ 06-21-2013 03:39 PM


Originally Posted by freeskier (Post 3886260)
First thing I would check is to make sure the control arms bolts are tight.

This. you definitely have control arm problems if your pinion is going up and down. Also take a look at the brackets themselves to make sure they aren't broken or rusted off. Bushings could be another culprit depending on how much movement is there.

I wouldn't drive it until you got it taken care of because you will have bigger problem if left unattended. I had a broken upper and by the time I realized it, the other upper broke and caused enough damage to the pinion bearing that I chewed up teeth on the R/P requiring an unexpected regear.

Malfunction 06-21-2013 04:19 PM

these are my uppers in the rear.

Rubicon Express Part r/ere3783 - Control Arm Rear Adjustable Upper Super-Flex TJ/LJ/ZJ/ Pair

I had four wheel parts replace the bushings on the rubber ends of the upper arms last year and it still did it after. The other end of the uppers, the Heim looking metal ones were never replaced and that end is connected to the axle while the rubber end is connected to the frame. The reason I suspect this end of the arm is because last year and 6k miles ago I did the following; New driveshaft and u joints all around, all new lower arm heimjoints, all new gears bearings and seals in both axles, transfercase rebuild, and the bushings on one end of the rear upper control arms. The only things not rebuilt on the rear axle are the trackbar bushings, the swaybar bushings and that one end of the upper arms. i have been chasing this problem since last year!

Unfortunately I rarely have help so finding someone who knew what to look at while I made the issue occur took me a while, along with a divorce and a custody battle and err...we are getting off topic:D I checked all the bolts on the uppers and they are tight along with the lowers.

Malfunction 06-22-2013 09:56 AM

I ordered 2 new rubicon express uppers, should I replace the trackbar bushings too?

JPi4.0 06-22-2013 10:24 AM


Originally Posted by Malfunction (Post 3888243)
I ordered 2 new rubicon express uppers, should I replace the trackbar bushings too?

Use a pry bar and pry all of the joints one at a time. It's usually easy to pry between the bracket and the joint. If any move change that joint. Best if wheels are off the ground.

Water Dog 06-22-2013 12:17 PM

Sounds to me like the locker might be engaged going around corners...could be what took out the bushings.

Malfunction 06-25-2013 05:52 PM

well crap! I Went to install the new uppers and discovered something I should have checked the first time I had them off. The frame brackets are supposed to have a hole around .375 -.390 and mine are wallowed out .430-.450 in some places. The only thing I can think of would be to updrill the holes on the frame brackets and the new control arm bushings to .500 and run some 1/2-20 bolts. I have no Idea what to do with the holes in the axle brackets,though. Has anyone else had to fix a problem like this?

this picture is showing the hole in the frame bracket and the gap between the screw and the wall of the hole.

This picture is of the brackets on the axle.

Malfunction 06-25-2013 06:04 PM

I might be able to get away with drilling them 7/16 and use 7/16 hardware. That still leaves the axle brackets though.

freeskier 06-25-2013 06:54 PM

10 Attachment(s)
If 7/16 fit's in the Rubicon Express joint without drilling then use that, likely the joint uses a hardened ball/sleeve and can't be drilled out. The bolt size doesn't need to be exactly the bracket/joint size, that's not what keeps the arm in place.

I just can't figure out what that second picture is.

Malfunction 06-25-2013 07:06 PM

The second picture is of the upper control arm bracket hole on the axle, there is a metal washer that is flat on two sides and the flats catch dimples on the bracket itself. The washer is not in the photo, this is what is behind the washer. I thought nearly .60 difference in bolt size to bracket hole size would be causing some movement. I dont know what else it could be with all the things I have already replaced. The bushings on both ends of the old arms are still good, the lowers are pretty new also.

Malfunction 06-25-2013 09:02 PM

Put the new arms in anyway, still does it. If its not those holes being wallowed out and all the control arms are good, no brackets are broken then what the heck could it be that causes the axle housing to move? This is driving me crazy!

Full Spool 06-25-2013 10:34 PM

To check for movement in bushings and bolts...
Put the jeep on flat ground, place in first gear with emergency brake off. Climb underneath and roll the jeep forward and back with your foot. Get it rocking back and forth to where it used the gearbox to stop and reverse its momentum. Watch the joints to see which one are moving.

If it's hopping and binding on asphalt while turning, I'll bet your locker is engaged.

Malfunction 06-26-2013 08:51 AM

Alright, I upsized the bolts and the movement is gone but the banging remains, the banging is coming from play in the driveshaft/ring and pinion. The play seems excessive but from what I read lockers and auto lockers have a lot of backlash. I will just take it easy on the skinny pedal!

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