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Discussion Starter #1
Hello, new member here.
I've been scouring the internet lately and can't find much info.
In regards to my 08 STS RWD Northstar

Does anyone have experience with the rear suspension? Such as upper or lower control arm, coil spring, trailing arm removal or knuckle bushing removal and replacement?
Since I bought the car in January I have been dealing with extra noisy shifts from drive to reverse and back along with a slight intermittent clunk/bump from the rear end during deceleration when the trans downshifts.
I've had it the dealership, which was pointless as they told me it was the stabilizer bar links, I didn't think that could be it but changed them anyway.
I changed the rear diff bushing for the energy suspension version which only added a bit more noticeable gear whine.
Had it at another shop where the mechanic told me it was normal and failed to diagnose anything wrong with the rear end or drive line.
Lastly I had it to a driveline specialist that found the whole knuckle assemblies and everything attached on both sides to be moving with the torque shift and suggested basically everything be replaced.
Looking at it myself it is seems most of the movement is stemming from the UCA bushings, but is moving the whole rear suspension assemblies with the shift of power so I'm not sure what other bushings have been stressed, honestly they all look pretty good.
After searching for parts it looks like there are no bushings available separate for the UCA, LCA or trailing arm. I found replacements for the 3 in the knuckle but not sure how they come out or go back in. $60 for all the bushings vs $240 each for the knuckles with new bushings already installed, if prefer to just change the bushings if possible.
Reading through the PDF service manual it seems that only the UCAs can be removed without dropping the cradle either partially or entirely, as long as they'll make it out around the coil springs, which the manual left unclear.
I have a hard time believing everything is shot at 60k. I don't want to replace anything expensive that I don't have to but I do realize the car is 12 years old and rubber doesn't last forever.
I bought UCAs to start there since they don't seem to parallel any of the other disassembly and were moving the most.
Any insight, tips, shortcuts are greatly appreciated.
- Jeremy
572420
 

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Hello, new member here.
I've been scouring the internet lately and can't find much info.
In regards to my 08 STS RWD Northstar

Does anyone have experience with the rear suspension? Such as upper or lower control arm, coil spring, trailing arm removal or knuckle bushing removal and replacement?
Since I bought the car in January I have been dealing with extra noisy shifts from drive to reverse and back along with a slight intermittent clunk/bump from the rear end during deceleration when the trans downshifts.
I've had it the dealership, which was pointless as they told me it was the stabilizer bar links, I didn't think that could be it but changed them anyway.
I changed the rear diff bushing for the energy suspension version which only added a bit more noticeable gear whine.
Had it at another shop where the mechanic told me it was normal and failed to diagnose anything wrong with the rear end or drive line.
Lastly I had it to a driveline specialist that found the whole knuckle assemblies and everything attached on both sides to be moving with the torque shift and suggested basically everything be replaced.
Looking at it myself it is seems most of the movement is stemming from the UCA bushings, but is moving the whole rear suspension assemblies with the shift of power so I'm not sure what other bushings have been stressed, honestly they all look pretty good.
After searching for parts it looks like there are no bushings available separate for the UCA, LCA or trailing arm. I found replacements for the 3 in the knuckle but not sure how they come out or go back in. $60 for all the bushings vs $240 each for the knuckles with new bushings already installed, if prefer to just change the bushings if possible.
Reading through the PDF service manual it seems that only the UCAs can be removed without dropping the cradle either partially or entirely, as long as they'll make it out around the coil springs, which the manual left unclear.
I have a hard time believing everything is shot at 60k. I don't want to replace anything expensive that I don't have to but I do realize the car is 12 years old and rubber doesn't last forever.
I bought UCAs to start there since they don't seem to parallel any of the other disassembly and were moving the most.
Any insight, tips, shortcuts are greatly appreciated.
- Jeremy View attachment 572420
Do you think it's really all that. Mine did same think and it was the upper differential bushing. It's junk. I replaced mine with polyurethane one for stsv. It's more firm. But hasn't made noise since 45k and I am at 100k now.
 

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I mean you changed it before. But if it wasn't pressed in correctly it will mimic the same situation you have going. It does have to be exact. But only bushings I would change is 53, 24, 21. Loosening all stabilizer bars and re tighten then re+align it. Our alignment is the death of bushings on this car
 

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Discussion Starter #4
I mean you changed it before. But if it wasn't pressed in correctly it will mimic the same situation you have going. It does have to be exact. But only bushings I would change is 53, 24, 21. Loosening all stabilizer bars and re tighten then re+align it. Our alignment is the death of bushings on this car
Thanks for the reply.
I did change the diff bushing out for a poly bushing, it was the Energy Suspension version. Others have used and reported good results. It's easier to install because it uses the existing outer sleeve from the O.E bushing, so just push the two halves in, insert the inner sleeve and bolt it all back together, so I don't see how I could have screwed that up. The diff doesn't seem to move when put from reverse to drive, and only slight deflection when throttle is applied with the brakes on. I'm not sure it was even a problem in the first place, I just had read so much about it being the culprit for similar issues so thought it would be a good place to start.
Watching the suspension assembly with the wheels off as it's being shifted from D to R and back with the brakes on the whole suspension noticeably moves fore and aft so that does seem to lend some credibility to the worn bushings theory, but I am sceptical that every single one is shot.
Unfortunately the only bushings available separately are the three in each knuckle for the LCA, trailing arm and shock 34,36,37. All of the rest come with the arms.
I already fought the right UCA out on Sunday and haven't really noticed much difference if any. I'm torn now whether to do the left since I have it already, or if it would just be a waste of time and 90$. I would have done both Sunday anyway if the right wouldn't have taken me so long. Good news is the right was the more difficult side to work on and now I'm experienced so the left should be quicker, hopefully.
As far as the stabilizer bars, are you saying to loosen the links and the bushings? The manual didn't specify to load them before tightening so I didn't, but I'm now wondering if that would've been a good idea. There are a lot of things I'm noticing the manual doesn't get specific on.
Sorry for the super long post, but thanks for entertaining. I've been beating my head against a wall with this, and can't get much feedback elsewhere.
 

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Thanks for the reply.
I did change the diff bushing out for a poly bushing, it was the Energy Suspension version. Others have used and reported good results. It's easier to install because it uses the existing outer sleeve from the O.E bushing, so just push the two halves in, insert the inner sleeve and bolt it all back together, so I don't see how I could have screwed that up. The diff doesn't seem to move when put from reverse to drive, and only slight deflection when throttle is applied with the brakes on. I'm not sure it was even a problem in the first place, I just had read so much about it being the culprit for similar issues so thought it would be a good place to start.
Watching the suspension assembly with the wheels off as it's being shifted from D to R and back with the brakes on the whole suspension noticeably moves fore and aft so that does seem to lend some credibility to the worn bushings theory, but I am sceptical that every single one is shot.
Unfortunately the only bushings available separately are the three in each knuckle for the LCA, trailing arm and shock 34,36,37. All of the rest come with the arms.
I already fought the right UCA out on Sunday and haven't really noticed much difference if any. I'm torn now whether to do the left since I have it already, or if it would just be a waste of time and 90$. I would have done both Sunday anyway if the right wouldn't have taken me so long. Good news is the right was the more difficult side to work on and now I'm experienced so the left should be quicker, hopefully.
As far as the stabilizer bars, are you saying to loosen the links and the bushings? The manual didn't specify to load them before tightening so I didn't, but I'm now wondering if that would've been a good idea. There are a lot of things I'm noticing the manual doesn't get specific on.
Sorry for the super long post, but thanks for entertaining. I've been beating my head against a wall with this, and can't get much feedback elsewhere.
Yeah it's headache for sure. I have only learned by trial and error my way. Yeah the rest diff bushing I had to remove mine and put it back in. No issues since. But not saying to have to do that. I would change them bushings then.. Just because. Also how does the bushing look between the diff and axle? I cannot for the life of me rember what it's called off hand. Mine was crack like pizza in a few spots. There's clinic l clunks... Which is usually rubber to metal... And clangs which is metal to metal. Sorry for my scientific terms there. Also is it a possibility it's your upper ball joints? Those will mimic those issues too?
 

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As far as the stabilizer bars, are you saying to loosen the links and the bushings?
[/QUOT
Yes losen them and retighten them. Also at that time check those bushings. Also when's last time your car was aligned? This bolts not torqed back correctly will premature wear on the arm bushings too. Sorry alot of what ifs. These cars so finicky at times.
 

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Discussion Starter #7
Yeah it's headache for sure. I have only learned by trial and error my way. Yeah the rest diff bushing I had to remove mine and put it back in. No issues since. But not saying to have to do that. I would change them bushings then.. Just because. Also how does the bushing look between the diff and axle? I cannot for the life of me rember what it's called off hand. Mine was crack like pizza in a few spots. There's clinic l clunks... Which is usually rubber to metal... And clangs which is metal to metal. Sorry for my scientific terms there. Also is it a possibility it's your upper ball joints? Those will mimic those issues too?
The flex discs seemed solid to me, that was also the first thing the drive line shop suspected and they said the driveshaft was good all around. Ball joints are included in the control arm assembly so they'll be brand new after this. The one I removed already still seemed pretty solid though.
I have been meaning to get an alignment but figured I'd wait until I got everything tightened up first.
 

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Really sucks. Seems only real way may be replacing all those. Then you'll have a fresh start. But consider...if your going to tackle that job...also replacing your rear shocks. Since there. Also inspect the rubber pads rear coils sit on. Then with 100% rear done. And alignment. Should be nothing else. Maybe alittle cheaper to start...would be opening your diff and checking everything in there and repack it. But all what you have check and done so far points to those bushings. You could also remove them and source out someone to rebuild them in poly to your speck. You can get them made that way and it would firm up the arms alot. May be cheaper-to low cost. Only catch is down time for it. If you have good shops near by try them first. Or ask on here also. Also drag shops and tractor shops. They make about anything reasonable.
 

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Really sucks. Seems only real way may be replacing all those. Then you'll have a fresh start. But consider...if your going to tackle that job...also replacing your rear shocks. Since there. Also inspect the rubber pads rear coils sit on. Then with 100% rear done. And alignment. Should be nothing else. Maybe alittle cheaper to start...would be opening your diff and checking everything in there and repack it. But all what you have check and done so far points to those bushings. You could also remove them and source out someone to rebuild them in poly to your speck. You can get them made that way and it would firm up the arms alot. May be cheaper-to low cost. Only catch is down time for it. If you have good shops near by try them first. Or ask on here also. Also drag shops and tractor shops. They make about anything reasonable.
Yep, hopefully replacing everything one at a time I'll stumble into a solution, disassembly should get me close enough to change out my leaky axle seal as well. I'll probably leave those expensive shocks alone until they show signs of needing replacement, but I don't think that job would be bad at all. Definitely plan on checking the coil spring insulators while I'm in there, even though I haven't been able to find replacements yet.
Thanks again
 
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