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wobble in the rear end


thorpe991
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Just to verify, you did the upper and lower bushings on the rearend yourself so you know it was actually done and torqued properly?

 

If a shop did it they may have done uppers only or lowers only.

 

You may want to check each bushing one by one again and retorque. Could also be a faulty rear shock causing some similar symptoms.

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@rchuish

 

Now you said rear control arms. Do you mean the trailing arm bushings? Those have an upper and a lower bar on both sides. To completely fix your wobble those are typically the culprits and both uppers and lowers need to be replaced.

 

Edit: before i replaced mine, i would get that wobble during everytime you are experiencing and when i would let off the accelerator and immediately get back on it. Replaced all 8 of those bushings completely fixed the issue.

Edited by Remus92
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Yes I did them all, and properly torqued them, I also did the front end as well. Still a lot of wobble in it, and still have to take my foot off the gas and try again while driving. I also replaced the shocks and struts, and the rear coil springs.

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Huh. That kind of leaves the panhard bushings as the only thing left, unless the attachment points for the trailing arms or panhard are damaged or rusting off, and that seems like something you would've noticed by now.

 

Any other symptoms? Mods? Was it like this when you got it or did you have it for a while before this developed?

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Other potential sources of vibration:

1. rear driveshaft out of balance or worn u-joints

2. bent axle shaft or wheel

 

Tire rotation or alignment recently? Do you have the means to do a run-out on the wheel flanges at all corners?

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I got it used, the previous owner never changed all the bushings so I ended having to do it. I don't think the axle or axle rods are bent. I have lifted it and turned the tires with the rear end off the ground. I didn't see any change in the gap on the brake drum, and the attachments are not rusting out. It is in AZ we don't really have snow and salt on our roads. I do know it needs an alignment, I haven't done it since replacing the front axles, and bushings. The Panhard bushings looked fairly new, and didn't have any rot or cracking. No other mods on it, it is factory the way it is. Regarding the drive shaft, I have been in a car with a bent drive shaft, this feels different, this is just driving down the road and I hit a bump and it starts to wobble.

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I did, until I went through and checked those as well, they are all tight and they are all good.

 

I double checked the trailing arms, one of the the nuts and bolts had worked loose, I turned it a turn and half before it was tight again. It didn't wobble from the rear end after that, now I have a front bushing that isn't tight in the front control arm and that is where I have any shifting from. I need to figure out how to make the bushing fit tight, I thought it might have been the bushing but both new ones were loose. The socket in the control arm is to big, I need to use loctite or something in it.

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What did you torque everything down to, btw? You should be somewhere above 110 ft-lbs.

 

Not sure I follow in the loose bushing part. Are you talking about the metal sleeve that the bolt goes through, which is embedded in the rubber? The bolt is loose in there?

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I torqued them down to about 115 ft-lbs, and the control arm socket is to big for the bushing, it is the correct bushing but it is loose when you put in the control arm. I just dropped in, no need for a press. I think I figured out the other problems though. I managed to get the control arm bushing issue fixed, when I was done putting it all back together I went through and checked all the bolts and nuts. Some of them had worked loose. So I went through and re-torqued them all. I only had it wobble twice after that, once when I drove over unevenly textured freeway concrete, and the other when I was driving over poorly maintained highway, the freeway was at 75mph, and the highway was 65. I think it at this point it is the best I can do, and the car just wasn't designed to go that fast. It was in built in the 96 and most places at that time did not allow speed limits above 55-65. If I drive it right it does fine now. Hopefully I fixed it and I now have a reliable and fun mode of transportation.

 

Thanks for the help and input.

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I'm a little concerned about that bushing that didn't require pressing. That's not normal or desirable. You might not want to redo it, but I'd suggest a new control arm. Otherwise, you're only holding the bushing stationary, and it will lead to noise and fatigue, among other things. Plus, the arm will be allowed to moved alone the bushing shell. Were talking about the front bushing on an arm, right?

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I agree the Hawairish there is something very wrong those nuts should never come loose, I have done uppers twice, lowers once used poly bushing on the bottom. I do 10 to 15 days of long run off road a year never had one come loose in 10000 Km of logging roads.

 

You need to determine what is wrong, but even the poly bushing required some grease and pressure to seat. It sounds like the the metal housing for the bushing is missing. That is a thin tube of metal inside the mount. See the red arrow in the image below, stock bushings need to pressed in they should not just 'drop in'

aLToten.jpg

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It was a flaw in the manufacturing of the bushing, I got everything worked out and the bushing in snug. I still have the wobble in the back, I spoke to a mechanic buddy of mine. He said that it sounds like the panhard arm, I will need to either take it out or have somebody push the car sideways while under it to make sure it is still good. I am pretty sure he is correct, those are the only bushings that have not been changed, and that could be causing the wobble. I'll keep you guys updated on how things go when I can get the bushings swapped out.

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  • 1 month later...

Ok guys, I have been on here a few times and I just can't seem to get rid of the rear end wobble. I have replaced all five of the control arm bushings, (ten bushings). I have replaced all the front end bushings, struts, shocks, and rear coil springs. I am at a loss, the rear end will wobble still at highway speeds. I have noticed that it only happens after I either accelerate rapidly, or decelerate rapidly (letting off the gas). The rear end will shift to the right and I can feel the whole car twist, and then the back end shift towards the passenger side. When the speed evens out the wobble will start and then will eventually calm down, sometimes not. It will also wobble like crazy when I go over a bump at an over pass. At this point I have to thoughts sell the thing as a lost cause and let somebody part it out. Or try one more thing to fix it, I have an idea of what it might be, but I wanted to get every bodies thoughts on the issue before deciding what the issue may be and wasting more money on it. Let me know what you all think.

Yes the car was on level ground when I torqued all the bolts down, and I torqued them down to 115 pounds, (not a precise torque wrench, and about five pounds low). Again let me know what you guys think and I'll go from there.

 

Thanks.

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I would start at the beginning of this thread... pretend like your the OP and go through each response he got step by step doing the foot work of rechecking things you already checked.

 

Not being rude but man your post is like dejavu.

 

EDIT: Oh wait you did post on here back in October, that's why I remembered it sounding the same.

 

What all have you done and inspected since last posting up?

seemed like you had some good advice to go from.

Edited by LittleFR
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I see I've replied to this previously. Given this latest symptoms list, my money is on the driver's side motor mount (if not both mounts).

 

Assuming for a moment that this motor mount is busted in the way I've personally seen it busted (upper half still bolted to the engine, the lower half still bolted to the subframe, each with their own big chunk of rubber still attached in between), here's why it makes sense:

 

At rest or low speeds, the engine is just sitting on the mount. Assuming the passenger mount is still intact, it's now just acting as a flexible pivot point for the engine.

Rapid acceleration will cause the engine to lift under torque; when the transmission shifts, the engine will come down on the mount.

Rapid deceleration (in the context of letting off the gas, as you noted), will also cause the engine to come down from being under torque.

Hitting a bump fast enough at freeway speed will bump the engine off the mount, and it will come back down.

At freeway speeds, the engine revolution may hit natural oscillation, potentially just bouncing on the mount (the same way an imbalanced tire and a worn shock or strut will cause the tire to just bounce up and down at a given speed...in case you've ever seen this before).

 

In all these scenarios, the 'falling' engine will land on the mount, compress the driver's side front suspension a little, which most likely will cause the passenger rear to lift in response. When one side of the rear lifts or compresses, the axle will shift left or right in response because of the panhard. Under those 'fast' conditions, only the PHB bushings can do anything to dampen that amplified response.

 

At a low speed, can you produce any minor bump when steadily accelerating while the transmissions kicks up to the next gear? That was the symptom in my buddy's truck. Looked fine at visual inspection, but the piece literally fell off the mount when I unbolted it. You may need a floor jack to lift that side of the engine from underneath, or a engine hoist to lift the engine a little. You might be able to see some lift from engine revving, but you really need some sort of torque load from the transmission and driveline to produce something distinguishable in that scenario.

Edited by hawairish
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  • 3 weeks later...

At low speeds I can hear a shift in weight and a clunking noise from the front end. I know for sure that the transmission mount is bad, and it sounds like from what I have found one or both of the motor mounts are bad. I will replace all three and see what happens. Thanks again for the info, I have been fighting with this thing for almost a year now. We'll see what happens. I will let you guys know if I have a pathfinder for sale in few months that can be used as a project. Thanks again for the help.

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You may need rear shocks as well if it's rocking back and forth really bad it could be a bad tire I paid $139 for the upper and lower trailing arms on eBay or Amazon if you feel a lot of rocking check your shock absorbers they may be going bad as well

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